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Notice of Opportunity To Comment on Model Safety Evaluation on Technical Specification Improvement To Modify Requirements Regarding Missed Surveillances Using the Consolidated Line Item Improvement Process
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[Federal Register: June 14, 2001 (Volume 66, Number 115)]
[Notices]
[Page 32400-32407]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14jn01-139]
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NUCLEAR REGULATORY COMMISSION
Notice of Opportunity To Comment on Model Safety Evaluation on
Technical Specification Improvement To Modify Requirements Regarding
Missed Surveillances Using the Consolidated Line Item Improvement
Process
AGENCY: Nuclear Regulatory Commission.
ACTION: Request for comment.
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SUMMARY: Notice is hereby given that the staff of the Nuclear
Regulatory Commission (NRC) has prepared a model safety evaluation (SE)
relating to the modification of requirements regarding missed
surveillances imposed on licensees through technical specifications.
The NRC staff has also prepared a model no significant hazards
consideration (NSHC) determination relating to this matter. The purpose
of these models is to permit the NRC to efficiently process amendments
that propose to modify requirements for missed surveillances. Licensees
of nuclear power reactors to which the models apply could request
amendments confirming the applicability of the SE and NSHC
determination to their reactors. The NRC staff is requesting comments
on the model SE and model NSHC determination prior to announcing their
availability for referencing in license amendment applications.
DATES: The comment period expires July 16, 2001. Comments received
after this date will be considered if it is practical to do so, but the
Commission is able to ensure consideration only for comments received
on or before this date.
ADDRESSES: Comments may be submitted either electronically or via U.S.
mail.
Submit written comments to: Chief, Rules and Directives Branch,
Division of Administrative Services, Office of Administration, Mail
Stop: T-6 D59, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001.
Hand deliver comments to: 11545 Rockville Pike, Rockville,
Maryland, between 7:45 a.m. and 4:15 p.m. on Federal workdays.
Copies of comments received may be examined at the NRC's Public
Document Room, 11555 Rockville Pike (Room O-1F21), Rockville, MD.
Comments may be submitted by electronic mail to CLIIP@nrc.gov.
FOR FURTHER INFORMATION CONTACT: Robert Dennig, Mail Stop: O-12H4,
Division of Regulatory Improvement Programs, Office of Nuclear Reactor
Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-
0001, telephone 301-415-1161.
SUPPLEMENTARY INFORMATION:
Background
Regulatory Issue Summary 2000-06, ``Consolidated Line Item
Improvement Process for Adopting Standard Technical Specification
Changes for Power Reactors,'' was issued on March 20, 2000. The
consolidated line item improvement process (CLIIP) is intended to
improve the efficiency of NRC licensing processes. This is accomplished
by processing proposed changes to the standard technical specifications
(STS) in a manner that supports subsequent license amendment
applications. The CLIIP includes an opportunity for the public to
comment on proposed changes to the STS following a preliminary
assessment by the NRC staff and finding that the change will likely be
offered for adoption by licensees. This notice is soliciting comment on
a proposed change to the STS that modifies requirements regarding
missed surveillances. The CLIIP directs the NRC staff to evaluate any
comments received for a proposed change to the STS and to either
reconsider the change or to proceed with announcing the
[[Page 32401]]
availability of the change for proposed adoption by licensees. Those
licensees opting to apply for the subject change to technical
specifications are responsible for reviewing the staff's evaluation,
referencing the applicable technical justifications, and providing any
necessary plant-specific information. Each amendment application made
in response to the notice of availability would be processed and
noticed in accordance with applicable rules and NRC procedures.
This notice involves the modification of requirements regarding
missed surveillances in technical specifications. This proposed change
was proposed for incorporation into the standard technical
specifications by all Owners Groups participants in the Technical
Specification Task Force (TSTF) and is designated TSTF-358. TSTF-358
can be viewed on the NRC's web page at
http://www.nrc.gov/NRR/sts/sts.htm.
Applicability
This proposed change to modify technical specification requirements
for missed surveillances is applicable to all licensees who currently
have or who will adopt, in conjunction with the proposed change,
technical specification requirements for a Bases control program
consistent with the Technical Specifications (TS) Bases Control Program
described in Section 5.5 of the applicable vendor's STS.
To efficiently process the incoming license amendment applications,
the staff requests each licensee applying for the changes addressed by
TSTF-358 using the CLIIP to include Bases for the proposed technical
specification consistent with the Bases proposed in TSTF-358. In
addition, for those licensees that have not adopted requirements for a
Bases control program by converting to the improved STS or by other
means, the staff requests that you include the requirements for a Bases
control program consistent with the STS in your request for the
proposed change. The need for a Bases control program stems from the
need for adequate regulatory control of some key elements of the
proposal that are contained in the proposed Bases for SR 3.0.3. The
staff is requesting that the Bases be included with the proposed
license amendments because, in this case, the changes to the technical
specifications and changes to the associated Bases form an integrated
change to a plant's licensing bases. To ensure that the overall change,
including the Bases, includes the appropriate regulatory controls, the
staff plans to condition the issuance of each license amendment on
incorporation of the changes into the Bases document and on requiring
the licensee to control the changes in accordance with the Bases
Control Program. The CLIIP does not prevent licensees from requesting
an alternative approach or proposing the changes without the requested
Bases and Bases control program. Variations from the approach
recommended in this notice may, however, require additional review by
the NRC staff and may increase the time and resources needed for the
review.
Public Notices
This notice requests comments from interested members of the public
within 30 days of the date of publication in the Federal Register.
Following the staff's evaluation of comments received as a result of
this notice, the staff may reconsider the proposed change or may
proceed with announcing the availability of the change in a subsequent
notice (perhaps with some changes to the safety evaluation or proposed
no significant hazards consideration determination as a result of
public comments). If the staff announces the availability of the
change, licensees wishing to adopt the change will submit an
application in accordance with applicable rules and other regulatory
requirements. The staff will in turn issue for each application a
notice of consideration of issuance of amendment to facility operating
license(s), a proposed no significant hazards consideration
determination, and an opportunity for a hearing. A notice of issuance
of an amendment to operating license(s) will also be issued to announce
the modification of requirements for missed surveillances for each
plant that applies for and receives the requested change.
Proposed Safety Evaluation
U.S. Nuclear Regulatory Commission
Office of Nuclear Reactor Regulation
Consolidated Line Item Improvement
Technical Specification Task Force (TSTF) Change TSTF-358
Change to Surveillance Requirement 3.0.3 Regarding Missed Surveillances
1.0 Introduction
In a letter dated November 17, 1999, the Nuclear Energy Institute
(NEI) Technical Specification Task Force (TSTF) proposed several
changes to the standard technical specifications (STS) (NUREGs 1430-
1434) on behalf of the industry. One of the proposed changes,
identified as TSTF-358, was a change to STS surveillance requirement
(SR) 3.0.3 regarding missed SRs. The proposed change would modify SR
3.0.3 to allow a delay period for a missed SR of 24 hours or up to the
surveillance frequency, whichever is longer.
On February 14, 2000, the staff requested that the NEI TSTF modify
TSTF-358 to address several questions and comments that the staff had
during their initial review of the proposed change. On September 15,
2000, the NEI TSTF submitted Revision 5 to TSTF-358 for review.
(Revisions 2-4 were only reviewed by the industry and were never
submitted for NRC review.) This proposal is one of the industry's
initiatives under the Risk-Informed Technical Specifications program.
The industry proposed changes, in TSTF-358, to the Technical
Specifications (TS) SR 3.0.3 and the SR 3.0.3 Bases have been modified
slightly by the NRC staff. The modifications are: (1) The TS SR 3.0.3
proposal has been changed, by the addition of a phrase to the proposed
new sentence, to make it clear that not only must a risk evaluation be
performed but also that the risk impact must be managed; and, (2) the
SR 3.0.3 Bases proposal is changed to properly invoke the program to
assess and manage risk required by 10 CFR 50.65(a)(4), and to avoid the
misperception that 10 CFR 50.65(a)(4) requires monitoring at times
other than before maintenance activities.
The following shows the TSTF-358 TS SR 3.0.3 and SR 3.0.3 Bases
with the NRC staff additions and deletions incorporated: (1) The
revised TS SR 3.0.3 reads, ``A risk evaluation shall be performed for
any surveillance delayed greater than 24 hours, and the risk shall be
managed;'' and (2) the revised SR 3.0.3 Bases that provides the link to
10 CFR 50.65(a)(4) reads, ``This risk impact should be managed through
the program in place to implement 10 CFR 50.65(a)(4) and its
implementation guidance, NRC Regulatory Guide 1.182, `Assessing and
Managing Risk Before Maintenance Activities at Nuclear Power Plants.'
2.0 Background
The regulations contained in 10 CFR 50.36, ``Technical
Specifications,'' require that technical specifications include
surveillance requirements. Surveillance requirements are requirements
relating to test, calibration, or inspection to ensure that the
necessary quality of systems and components is maintained, that
facility operation will be within safety limits, and that the limiting
conditions for operation will be met. Technical specifications (TS)
require surveillance tests to be performed periodically (e.g., weekly
or monthly). The periodic test
[[Page 32402]]
interval defined in the technical specifications is called the
surveillance frequency or surveillance interval. The majority of
surveillance tests included in the technical specifications are
designed to ensure that standby safety systems will be operable when
they are needed to mitigate an accident. By testing these components,
failures that may have occurred since the previous test can be detected
and corrected.
STS SR 3.0.1 states that SRs shall be met during the MODES or other
specified conditions in the applicability for individual limiting
conditions for operation (LCOs) and that failure to perform a
surveillance within the specified frequency shall be failure to meet
the LCO, except as provided in SR 3.0.3.
The current STS SR 3.0.3 requires that, if it is found that a
surveillance test was not performed within its specified frequency, the
associated LCO be declared not met (e.g., equipment be declared
inoperable) unless the missed surveillance test is completed
successfully within 24 hours or within the limit of the specified
frequency, whichever is less, from the time it was discovered that the
test was not performed. The requirements in STS SR 3.0.3 are based on
NRC Generic Letter 87-09, ``Sections 3.0 and 4.0 of the Standard
Technical Specifications (STS) of the Applicability of Limiting
Conditions for Operation and Surveillance Requirements.''
Generic Letter 87-09 was published to address three specific issues
with the application of technical specifications. One of those issues
was missed surveillances. The Generic Letter states, ``The second
problem involves unnecessary shutdowns caused by Specification 4.0.3
when surveillance intervals are inadvertently exceeded. The solution is
to clarify the applicability of the Action Requirements, to specify a
specific acceptable time limit for completing a missed surveillance in
certain circumstances, and to clarify when a missed surveillance
constitutes a violation of the Operability Requirements of an LCO. It
is overly conservative to assume that systems or components are
inoperable when a surveillance has not been performed because the vast
majority of surveillances do in fact demonstrate that systems or
components are OPERABLE. When a surveillance is missed, it is primarily
a question of operability that has not been verified by the performance
of a Surveillance Requirement. Because the allowable outage time limits
of some Action Requirements do not provide an appropriate time for
performing a missed surveillance before Shutdown Requirements apply,
the technical specifications should include a time limit that allows a
delay of required actions to permit the performance of the missed
surveillance based on consideration of plant conditions, adequate
planning, availability of personnel, the time required to perform the
surveillance, and, of course, the safety significance of the delay in
completing the surveillance. [emphasis added]
The staff has concluded
that 24 hours is an acceptable time limit for completing a missed
surveillance when the allowable outage times of the Action Requirements
are less than this limit, or when time is needed to obtain a temporary
waiver\1\ of the Surveillance Requirement.''
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\1\ The terminology ``temporary waiver'' was subsequently
revised to refer to the practice as ``enforcement discretion.''
---------------------------------------------------------------------------
The proposed change would extend the delay time for declaring the
LCO not met and entering the required actions by allowing more time to
perform the missed surveillance test. This will be achieved by
modifying [SR 3.0.3]
to allow a delay period from 24 hours up to the
surveillance frequency, whichever is greater, to perform a missed
surveillance prior to having to declare the LCO not met. The change
will add a sentence to [SR 3.0.3]
that states, ``A risk evaluation
shall be performed for any surveillance delayed greater than 24 hours,
and the risk impact shall be managed.''
The objective of the proposed change is to minimize the impact on
plant risk resulting from the performance of a missed surveillance test
by allowing flexibility in considering the plant conditions and other
plant activities without compromising plant safety. In addition,
implementation of the proposed change would reduce the need for the
licensee to apply for regulatory relief to delay the performance of
missed surveillances.
The basis for establishing the changes to requirements for missed
surveillances in Generic Letter 87-09 continues to apply to the current
proposed change to [SR 3.0.3]. As evidenced by the discussion in
Generic Letter 87-09, the intent of the change proposed in the Generic
Letter was to reduce the impact on plant risk resulting from the
performance of a missed surveillance test by allowing some flexibility
in the performance of missed tests. The delay time of 24 hours was
selected using engineering judgement in the absence of suitable tools
to determine a delay period on a case-by-case basis. In addition, the
staff recognized in Generic Letter 87-09 that even a 24-hour delay
period would not be sufficient in some cases and licensees would need
to seek regulatory relief in those cases.
The recent revision to the Maintenance Rule to establish the
requirement in 10 CFR 50.65(a)(4) to assess and manage the increase in
risk that may result from maintenance activities provides a framework
to allow a more risk-informed approach to addressing missed
surveillances. This approach is consistent with the Commission's policy
to increase the use of probabilistic risk assessment (PRA) technology
in all regulatory matters to the extent supported by the state-of-the-
art in PRA methods and data and continues to support the objectives
outlined by the staff in Generic Letter 87-09.
2.1 Background Determination
The staff believes that the proposed change to [SR 3.0.3]
is
appropriate because: (1) The number of missed surveillance tests is a
very small fraction of the total number of such tests performed at a
nuclear plant each year; (2) the change applies to unintentionally
missed surveillance tests and is not intended to be used as an
operational convenience to extend surveillance frequencies (as stated
in the proposed [SR 3.0.3]
Bases); and (3) missed surveillances will be
placed in the licensee's corrective action program.
The staff has determined that the proposed change is applicable to
all licensees. In Generic Letter 87-09, the staff concluded that the
proposed modifications would result in improved technical
specifications for all plants and no limitations were put on the
applicability of the proposed changes. Because the basis for this
proposed change is largely the same as for the change proposed in
Generic Letter 87-09, the staff believes the same broad applicability
is appropriate. In addition, every licensee is required to comply with
the Maintenance Rule and, therefore, will have implemented programs to
comply with 10 CFR 50.65(a)(4) to assess and manage risk associated
with maintenance and other operational activities.
3.0 Evaluation
The proposed change modifies [SR 3.0.3]
to allow a delay period
from 24 hours up to the surveillance frequency, whichever is greater,
to perform a missed surveillance prior to having to declare the LCO not
met. The change will add a sentence to [SR 3.0.3]. that states, ``A
risk evaluation shall be performed for any surveillance delayed
[[Page 32403]]
greater than 24 hours, and the risk impact shall be managed.''
The proposed change will not allow equipment known to be inoperable
to be considered operable until the missed surveillance is performed.
If it is known that the missed surveillance could not be met, [SR
3.0.1]
would require that the LCO be declared not met and the
appropriate condition(s) entered. In addition, the Bases for [SR 3.0.3]
state that the use of the delay period established by [SR 3.0.3]
is a
flexibility which is not intended to be used as an operational
convenience to extend surveillance intervals, but only for the
performance of missed surveillances.
The modification will also include changes to the Bases for [SR
3.0.3]
that provide details on how to implement the new requirements.
The Bases changes provide guidance for surveillance frequencies that
are not based on time intervals but are based on specified unit
conditions, operating situations, or requirements of regulations. In
addition, the Bases changes state that the licensee is expected to
perform any missed surveillance test at the first reasonable
opportunity, taking into account appropriate considerations, such as
the impact on plant risk and accident analysis assumptions,
consideration of unit conditions, planning, availability of personnel,
and the time required to perform the surveillance. The Bases also state
that the risk impact should be managed through the program in place to
implement 10 CFR 50.65(a)(4) and its implementation guidance, NRC
Regulatory Guide 1.182, ``Assessing and Managing Risks Before
Maintenance Activities at Nuclear Power Plants,'' and that the missed
surveillance should be treated as an emergent condition as discussed in
Regulatory Guide 1.182. In addition, the Bases state that the degree of
depth and rigor of the evaluation should be commensurate with the
importance of the component and that missed surveillances for important
components should be analyzed quantitatively. The Bases also state
that, if the results of the risk evaluation determine that the risk
increase is significant, the evaluation should be used to determine the
safest course of action. Finally, the Bases state that all missed
surveillances will be placed in the licensee's Corrective Action
Program.
[Optional Section for applications for changes to technical
specifications that do not include a Bases Control Program:
The licensee has included in its application the addition of a
Bases control program to the administrative section of the technical
specifications. Prior the issuance of the STS (NUREGS 1430-1434), the
control of technical specification Bases was not clearly defined by
either technical specifications or NRC regulations. The administrative
requirements for a Bases control program were added to the STS to
define a methodology for evaluating changes to and providing updates of
the technical specification Bases. The addition of the technical
specification Bases Control Program for plants that have not adopted
the STS will provide the same benefits in terms of defining a
methodology for the maintenance of the technical specification Bases.
The licensee has proposed administrative controls that are consistent
with the STS requirements and therefore satisfy the condition that was
included in the Federal Register Notice for the use of CLIIP for this
technical specifications change. The staff finds the addition of the
technical specifications Bases Control Program acceptable.]
Key elements provided by the licensee to justify the proposed
technical specification change are listed below. These elements were
built into the process to ensure that every time a surveillance is
missed the risk will be properly assessed and managed. In addition,
such elements facilitate regulatory oversight.
A risk evaluation shall be performed for any surveillance
test delayed longer than 24 hours and the risk impact shall be managed.
Although the proposed change to [SR 3.0.3]
allows an
increase of the delay time, the missed surveillance test should be
performed at the ``first reasonable opportunity.''
The ``first reasonable opportunity'' will be determined by
taking into consideration the risk impact from delaying the
surveillance test (including risk from changing plant configurations or
shutting the plant down to perform the surveillance, whenever
applicable) as well as the impact on any analysis assumptions, in
addition to unit conditions, planning, availability of personnel, and
the time required to perform the surveillance.
A missed surveillance will be treated as an emergent
condition in the same fashion as other unplanned maintenance
activities. The risk impact of the condition will be managed through
the program in place to implement 10 CFR 50.65(a)(4) and its
implementation guidance, Regulatory Guide 1.182 .
A missed surveillance will be placed in the licensee's
corrective action program, thus providing the staff with a means to
verify that the number of missed surveillances continues to be very
low.
The NRC's operating reactor oversight process will provide
the framework for inspectors and other staff to review missed
surveillances and assess the licensee's actions and performance.
The staff finds that a process containing these key elements is
appropriate in this case for the following reasons:
10 CFR 50.65(a)(4) requires licensees to implement
programs to assess and manage increases in risk that may result from
planned maintenance activities. This program is suitable to assess and
manage the risk impact of missed surveillances because missed
surveillances can be treated as emergent conditions and their risk
impact will be assessed and managed in an integrated fashion with
concurrent maintenance activities.
Inspection procedures are in place which will allow NRC
staff to oversee the implementation of Maintenance Rule requirements,
including the adequacy of risk assessments performed by licensees for
maintenance configurations.
The number of missed surveillance tests is a very small
fraction of the total number of such tests performed at a nuclear plant
each year. The proposed change is not intended to be used as an
operational convenience to extend surveillance frequencies.
This process is similar to other improvements that have
been made to the technical specifications that allow the use of a
controlled decision making process by licensees when the process has
some high-level regulatory oversight. Two examples of this are the
adoption of the Core Operating Limits Report and the Pressure/
Temperature Limits Report. In each of these cases, the staff approved
the methodology behind the calculation of certain technical
specification parameter limits and then allowed the specific limits to
be removed from technical specifications and controlled by the licensee
using the approved methodology. Similarly, for this proposed change,
the staff has already approved guidance that outlines a process for
complying with 10 CFR 50.65(a)(4) and, therefore, can allow the
licensee to use that guidance to determine the most prudent course of
action in the case of a missed surveillance.
The guidance outlining an acceptable process for licensees to
assess and manage increases in risk that may result from planned
maintenance activities is found in Regulatory Guide 1.182. Regulatory
Guide 1.182 endorses a
[[Page 32404]]
revised Section 11 to NUMARC 93-01 ``Industry Guideline for Monitoring
the Effectiveness of Maintenance at Nuclear Power Plants,'' Revision 2,
updated by the Nuclear Energy Institute.
Section 11 of NUMARC 93-01, dated February 22, 2000, provides
guidance for assessing and managing risk impact resulting from
performance of maintenance activities, including guidance for
establishing action thresholds based on qualitative and quantitative
considerations as well as risk management actions. The objective of
risk management is to control the temporary and aggregate risk
increases from maintenance activities such that the plant's average
baseline risk is maintained within a minimal range. This is
accomplished by using the results of the risk assessment to plan and
schedule maintenance such that the risk increases are limited, and to
take additional actions beyond routine work controls to address
situations where the temporary risk increase is above a certain
threshold.
In order to gain additional insights into the proposed change, the
staff referred to the regulatory guidance provided in Regulatory Guide
1.174 entitled ``An Approach for Using Probabilistic Risk Assessment in
Risk-Informed Decisions on Plant-Specific Changes to the Licensing
Basis, and in Regulatory Guide 1.177, ``An Approach for Plant-Specific,
Risk-Informed Decisionmaking: Technical Specifications,'' although
these Regulatory Guides do not specifically address the type of change
in this proposal. Regulatory Guide 1.177 provides the staff's
recommendations for utilizing risk information to evaluate changes to
nuclear power plant technical specifications by assessing the impact of
such proposed changes on the risk associated with plant operation. The
approach documented in Regulatory Guide 1.177 was taken into
consideration by the staff in evaluating the risk information provided
in support of the proposed changes in [SR 3.0.3]
to increase the time
allowed to perform a missed surveillance.
One portion of the guidance in Regulatory Guide 1.177 includes the
assessment of the risk impact of the proposed change for comparison to
acceptance guidelines consistent with the Commission's Safety Goal
Policy Statement, as documented in Regulatory Guide 1.174. In addition,
the approach outlined in the guidance aims at ensuring that the plant
risk does not increase unacceptably at any time during the
implementation of the proposed change (i.e., during the extended
surveillance interval).
Another portion of the guidance addresses the need for identifying
risk significant configurations resulting from maintenance or other
operational activities and taking appropriate compensatory measures to
avoid such configurations. This type of evaluation is directly
addressed by the requirement to perform a risk assessment for missed
surveillances delayed longer than 24 hours.
The staff believes that insights from the guidance provided in
Regulatory Guides 1.174 and 1.177 can be used to show how the proposed
change is expected to result in, at most, an increase in risk which is
small and consistent with the Commission's Safety Goal Policy
Statement. The staff believes that in the majority of the cases of
missed surveillances, implementation of the proposed change will result
in a risk benefit due to the proposed requirement for the licensee to
evaluate the risk impact for missed surveillances that would require a
delay of longer than 24 hours.
3.1 Risk Impact of the Proposed Change
The staff made a qualitative assessment of the risk impact of the
proposed change for comparison with the intent of the acceptance
guidelines documented in Regulatory Guide 1.174, consistent with the
Commission's Safety Goal Policy Statement. Such risk impact is measured
by the average (yearly) risk change. In addition, the staff took into
consideration guidance in Regulatory Guide 1.177 aimed at ensuring that
the plant risk does not increase unacceptably at any time during the
implementation of the proposed change (i.e., during an extended
surveillance interval in this case). The staff's qualitative assessment
is summarized below.
Average Risk Impact
The probability that a standby active component, such as a pump or
a circuit breaker, will fail when demanded during an accident is based
on the assumption that the component fails due to ``standby'' stresses
(i.e., stresses which are present while the component is in standby,
such as corrosion, dirt, lack of lubrication). This probability, also
called the component's average ``unavailability,'' is used in
probabilistic risk assessments (PRAs) and is most frequently calculated
by the following equation.
q = \1/2\ * l * T (1)
where:
q = the component's average unavailability,
l = the component's failure rate (assumed constant) while
in standby, and
T = the interval at which the component is tested for operability.
The average unavailability of a structure, system, or component
(SSC), calculated by using the above equation, reflects the potential
vulnerability of the component to ``standby'' stresses. Such
vulnerability increases with time between operability checks (tests)
assuming corrective action is taken to restore failed components
identified by the test. Thus, the risk impact of a missed surveillance
is reflected by the increased unavailability of the related SSCs due to
the increase of the interval between surveillance tests. If the missed
surveillance affects two or more components, some ``standby'' stresses
may impact multiple components. In such a case, the missed surveillance
would also increase the average common cause failure (CCF)
unavailability of two or more components and this should be addressed
in the risk assessment (CCF unavailabilities are calculated by
adjusting the single component failure unavailability using standard
PRA techniques, such as the beta factor or the Multiple Greek Letter
method).
The thresholds of the aggregate risk impacts are based on the
permanent change guidelines discussed in Regulatory Guide 1.174. The
licensee will be expected to manage the risk from the proposed
technical specification change in conjunction with the risk from other
concurrent plant activities to ensure that any risk increase, in terms
of CDF and LERF, will be small and consistent with the Commission's
Safety Goal Policy Statement.
Risk insights from existing PRAs and the low frequency of missed
surveillances indicate that the proposed technical specification change
is highly unlikely to lead to a significant increase in the average
(yearly) risk, in terms of CDF or LERF. Significant risk increases can
occur only under the following conditions:
The number of missed surveillances is allowed to increase
significantly;
High risk configurations are allowed (e.g., by allowing
certain combinations of multiple missed surveillances and/or outages);
and
Poor risk management of plant operational activities is
allowed.
Any of these conditions would be in violation of the intent of the
proposed [SR 3.0.3]
and could trigger a review by NRC of the licensee's
actions and performance. The implementation guidance found in the
proposed [SR 3.0.3]
Bases is intended to ensure that
[[Page 32405]]
such conditions would not occur. Licensees are already required to
manage risk associated with online maintenance activities. Furthermore,
the addition of missed surveillances (rather rare plant conditions) to
the maintenance activities is not expected to increase risk. On the
contrary, insights from existing risk assessments indicate that there
are plant conditions during which it is preferable and safer not to
have to complete missed surveillance tests for some SSCs. Therefore,
the proposed technical specification change will allow the licensee to
make informed decisions and take appropriate actions to control risk.
Temporary Risk Impact
In addition to changes in the mean values of CDF and LERF, the
incremental conditional core damage probability (ICCDP) and the
incremental conditional large early release probability (ICLERP) are
proposed by Regulatory Guide 1.177 as appropriate measures of the
increase in probability of core damage and large early release,
respectively, during the period of implementation of a proposed
technical specification change (i.e., during the extended surveillance
period in the case of a missed surveillance). Regulatory Guide 1.182
provides guidance for controlling temporary risk increases resulting
from maintenance activities. Such guidance, which is consistent with
guidance provided in Regulatory Guide 1.177, establishes action
thresholds based on qualitative and quantitative considerations as well
as risk management actions. The staff expects that the licensee will
implement this guidance for assessing temporary risk increases from
missed surveillances concurrently with maintenance and other
operational activities.
Instantaneous and temporary risk increases from a missed
surveillance are assessed by considering the time-dependent
unavailability, most often calculated by the following equation.
q(t) = l * t
where:
q(t) = the component's unavailability at time t
= the component's failure rate (assumed constant) while
in standby, and
t = time from end of surveillance frequency of a missed
surveillance test.
If the missed surveillance affects two or more components, some
``standby'' stresses may impact multiple components. In such a case,
the missed surveillance would increase also the time-dependent CCF
unavailability of two or more components and this should be addressed
in the risk assessment.
Significant temporary risk increases following a missed
surveillance can occur only under the following conditions:
High risk configurations are allowed (e.g., by allowing
certain combinations of multiple missed surveillances and/or outages),
and
Poor risk management of plant operation activities is
allowed.
Any of these conditions would be in violation of the intent of the
proposed [SR 3.0.3]
and could trigger an NRC review of the licensee's
actions and performance. The requirements associated with the proposed
change are intended to ensure that such conditions would not occur.
Thus, the proposed technical specification change is not expected to
lead to significant temporary risk increases. Following the discovery
of an unintentionally missed surveillance, the licensee will have to
assess temporary risk increases, qualitatively or quantitatively
depending on the importance of the component affected by the missed
surveillance, if the surveillance cannot be performed within 24 hours
from the time it has been discovered.
3.2 Risk-Informed Configuration Risk Management
Regulatory Guide 1.177 addressed the need for identifying risk
significant configurations resulting from maintenance or other
operational activities and taking appropriate compensatory measures to
avoid such configurations. The objective of such guidance for this
review is to ensure that plant safety will be maintained and monitored
during the period of an extended surveillance testing interval
(associated with an unintentionally missed surveillance). The licensee
proposes to use the program in place to implement the Maintenance Rule
to identify ``high-risk'' configurations resulting from missed
surveillance tests in conjunction with outages associated with
maintenance activities. It is worth noting that the guidance provided
in Regulatory Guide 1.177 with regard to the Configuration Risk
Management Program was used as the basis for developing the guidance
contained in Regulatory Guide 1.182 for the 10 CFR 50.65(a)(4)
provisions of the Maintenance Rule. This provides additional assurance
that the proposed process for evaluating the risk impact of missed
surveillances is consistent with guidance provided in Regulatory Guide
1.177.
3.3 Quality of PRA
Once a missed surveillance is discovered and the licensee
determines that the surveillance cannot be performed within 24 hours,
the licensee will have to use a risk assessment to determine the most
prudent course of action. The risk assessment can be done qualitatively
or quantitatively depending on the importance of the component affected
by the missed surveillance (missed surveillances for risk important
components should be analyzed quantitatively). Such a risk assessment
will be consistent with the program to implement the Maintenance Rule
guidance to assess and account for both aggregate and temporary risk
increases associated with ``emergent'' plant conditions as well as
before undertaking online maintenance or other operational activities.
All licensees must have the capability to assess and manage
increases in risk from maintenance activities as required by the
Maintenance Rule. Risk assessments performed pursuant to 10 CFR
50.65(a)(4) may use qualitative, quantitative or blended methods. The
degree of depth and rigor of the evaluation should be commensurate with
the complexity of the proposed configuration to be assessed. Section 11
of NUMARC 93-01 provides guidance for using qualitative, quantitative
or blended methods to assess risk. Current inspection programs allow
the NRC staff to oversee licensee implementation of 10 CFR 50.65(a)(4)
requirements, including the adequacy of pre-maintenance risk
assessments performed by licensees.
For the reasons listed below, the staff finds that the same
``quality'' of PRA or PRA insights used to perform risk assessments
pursuant to 10 CFR 50.55 (a)(4) is also appropriate when assessing the
impact of missed surveillances.
The number of ``emergent'' conditions resulting from
missed surveillances is very small (in both absolute terms and in
comparison to the frequency of ``emergent'' conditions resulting from
equipment failures). The licensee is expected to implement the proposed
change to [SR 3.0.3]
in a manner that ensures that this statement
remains valid.
A missed surveillance is equivalent to a one-time
surveillance frequency extension. Therefore, the risk exposure is
limited to the duration of the surveillance frequency extension. Risk
increases are small compared to similar increases associated with
equipment failures. The average (conditional) risk increase, given a
missed surveillance, may be comparable to the risk increase
[[Page 32406]]
from equipment failures. However, due to the rarity of missed
surveillances, the average (yearly) risk increase from missed
surveillances is expected to be small compared to the risk increase
from equipment failures.
PRA insights indicate that the risk impact from missed
surveillances is significant only for a relatively small set of standby
equipment. This equipment, such as auxiliary feedwater, high pressure
injection pumps, and emergency diesel generators, is located outside
containment and generally can be easily tested in a short time, if
necessary.
NRC inspection programs allow NRC staff to oversee the
implementation of 10 CFR 50.65 (a)(4) requirements, including the
adequacy of pre-maintenance risk assessments performed by licensees.
3.4 Summary
The staff review finds that the process proposed by the licensee
for addressing missed surveillance requirements meets Commission
guidance for allowing technical specification changes. Key elements of
the proposed change are listed below.
A risk evaluation shall be performed for any surveillance
delayed longer than 24 hours, and the risk impact shall be managed.
The missed surveillance test should be performed at ``the
first reasonable opportunity.''
The ``first reasonable opportunity'' will be determined by
taking into consideration the risk impact from delaying the
surveillance test as well as the impact on any analysis assumptions, in
addition to unit conditions, planning, availability of personnel, and
the time required to perform the surveillance.
A missed surveillance will be treated as an ``emergent''
condition in the same fashion as other unplanned maintenance
activities. The risk impact of the condition will be managed through
the program in place to implement 10 CFR 50.65(a)(4) and its
implementation guidance (NRC Regulatory Guide 1.182). Rescheduling of
missed surveillances pursuant to Regulatory Guide 1.182 will ensure the
necessary provisions for managing the risk impact of performing the
surveillance in conjunction with other ongoing plant configuration
changes.
The NRC's operating reactor oversight process will provide
the framework for inspectors and other staff to review missed
surveillances and assess the licensee's actions and performance.
Inspection procedures are in place which will allow NRC staff to
oversee the implementation of Maintenance Rule requirements, including
the adequacy of pre-maintenance risk assessments performed by
licensees.
A missed surveillance will be placed in the licensee's
corrective action program, thus providing the staff with a means to
verify that the number of missed surveillances continues to be very
low.
The number of missed surveillance tests is a very small
fraction of the total number of such tests performed at a nuclear plant
each year. The proposed change is not intended to be used as an
operational convenience to extend surveillance frequencies.
This process is similar to other improvements that have
been made to the technical specifications that allow the use of a
controlled decision making process by licensees when the process has
some high-level regulatory oversight. Two examples of this are the
adoption of the Core Operating Limits Report and the Pressure/
Temperature Limits Report. In each of these cases, the staff approved
the methodology behind the calculation of certain technical
specification parameter limits and then allowed the specific limits to
be removed from technical specifications and controlled by the licensee
using the approved methodology. Similarly, for this proposed change,
the staff has already approved guidance that outlines a process for
complying with 10 CFR 50.65(a)(4) and, therefore, can allow the
licensee to use that guidance to determine the most prudent course of
action in the case of a missed surveillance.
For these reasons, the staff finds that the proposed technical
specification change, to be implemented in accordance with the above
listed key elements, is acceptable.
4.0 State Consultation
In accordance with the Commission's regulations, the [ ]
State
official was notified of the proposed issuance of the amendment. The
State official had [(1) no comments or (2) the following comments--with
subsequent disposition by the staff].
5.0 Environmental Consideration
The amendment changes a requirement with respect to a surveillance
requirement. [For those adding a Bases Control Program: The amendment
also changes recordkeeping, reporting, or administrative procedures or
requirements.]
The NRC staff has determined that the amendments involve
no significant increase in the amounts and no significant change in the
types of any effluents that may be released offsite, and that there is
no significant increase in individual or cumulative occupational
radiation exposure. The Commission has previously issued a proposed
finding that the amendments involve no significant hazards
consideration, and there has been no public comment on such finding
(FR). Accordingly, the amendments meet the eligibility criteria for
categorical exclusion set forth in 10 CFR 51.22(c)(9) [and c(10)].
Pursuant to 10 CFR 51.22(b) no environmental impact statement or
environmental assessment need be prepared in connection with the
issuance of the amendments.
6.0 Conclusion
The Commission has concluded, based on the considerations discussed
above, that (1) there is reasonable assurance that the health and
safety of the public will not be endangered by operation in the
proposed manner, (2) such activities will be conducted in compliance
with the Commission's regulations, and (3) the issuance of the
amendments will not be inimical to the common defense and security or
to the health and safety of the public.
Proposed No Significant Hazards Consideration Determination
Description of Amendment Request: A change is proposed to technical
specifications to allow a longer period of time to perform a missed
surveillance. The time is extended from the current limit of up to 24
hours or up to the limit of the specified frequency, whichever is less;
to up to 24 hours or up to the limit of the specified frequency,
whichever is greater.
Basis for proposed no significant hazards consideration
determination: As required by 10 CFR 50.91(a), an analysis of the issue
of no significant hazards consideration is presented below:
Criterion 1--The Proposed Change Does Not Involve a Significant
Increase in the Probability or Consequences of an Accident Previously
Evaluated
The proposed change relaxes the time allowed to perform a missed
surveillance. The time between surveillances is not an initiator of any
accident previously evaluated. Consequently, the probability of an
accident previously evaluated is not significantly increased. The
equipment being tested is still required to be operable and capable of
performing the accident mitigation functions assumed in the accident
analysis. As a result, the consequences of any accident previously
evaluated are not
[[Page 32407]]
significantly affected. Any reduction in confidence that a standby
system might fail to perform its safety function due to a missed
surveillance is small and would not, in the absence of other unrelated
failures, lead to an increase in consequences beyond those estimated by
existing analyses. The addition of a requirement to assess and manage
the risk introduced by the missed surveillance will further minimize
possible concerns. Therefore, this change does not involve a
significant increase in the probability or consequences of an accident
previously evaluated.
Criterion 2--The Proposed Change Does Not Create the Possibility of a
New or Different Kind of Accident From Any Previously Evaluated
The proposed change does not involve a physical alteration of the
plant (no new or different type of equipment will be installed) or a
change in the methods governing normal plant operation. A missed
surveillance will not, in and of itself, introduce new failure modes or
effects and any increased chance that a standby system might fail to
perform its safety function due to a missed surveillance would not, in
the absence of other unrelated failures, lead to an accident beyond
those previously evaluated. The addition of a requirement to assess and
manage the risk introduced by the missed surveillance will further
minimize possible concerns. Thus, this change does not create the
possibility of a new or different kind of accident from any accident
previously evaluated.
Criterion 3--The Proposed Change Does Not Involve a Significant
Reduction in the Margin of Safety
The extended time allowed to perform a missed surveillance does not
result in a significant reduction in the margin of safety. As supported
by the historical data, the likely outcome of any surveillance is
verification that the LCO is met. Failure to perform a surveillance
within the prescribed frequency does not cause equipment to become
inoperable. The only effect of the additional time allowed to perform a
missed surveillance on the margin of safety is the extension of the
time until inoperable equipment is discovered to be inoperable by the
missed surveillance. However, given the rare occurrence of inoperable
equipment, and the rare occurrence of a missed surveillance, a missed
surveillance on inoperable equipment would be very unlikely. This must
be balanced against the real risk of manipulating the plant equipment
or condition to perform the missed surveillance. In addition, parallel
trains and alternate equipment are typically available to perform the
safety function of the equipment not tested. Thus, there is confidence
that the equipment can perform its assumed safety function.
Therefore, this change does not involve a significant reduction in
a margin of safety.
Based upon the reasoning presented above and the previous
discussion of the amendment request, the requested change does not
involve a significant hazards consideration.
Dated at Rockville, Maryland, this 8th day of June 2001.
For the Nuclear Regulatory Commission.
Robert L. Dennig,
Acting Chief, Technical Specification Branch, Division of Regulatory
Improvement Programs, Office of Nuclear Reactor Regulation.
[FR Doc. 01-14978 Filed 6-13-01; 8:45 am]
BILLING CODE 7590-01-P