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Tennessee Valley Authority, Watts Bar Nuclear Plant, Unit 1; Environmental Assessment and Finding of No Significant Impact
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: August 26, 2002 (Volume 67, Number 165)]
[Notices]
[Page 54826-54828]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr26au02-72]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-390]
Tennessee Valley Authority, Watts Bar Nuclear Plant, Unit 1;
Environmental Assessment and Finding of No Significant Impact
The U.S. Nuclear Regulatory Commission (NRC) is considering
issuance of an amendment to Facility Operating License No. NPF-90 held
by the Tennessee Valley Authority (TVA or the licensee) for operation
of the Watts Bar Nuclear Plant (WBN), Unit 1, located in Rhea County,
Tennessee. Therefore, as required by Title 10, Code of Federal
Regulations (10 CFR), Sec. 51.21, the NRC is issuing this environmental
assessment and finding of no significant impact.
Environmental Assessment
Identification of the Proposed Action
The proposed action would change WBN's Technical Specifications to
allow TVA to irradiate up to 2304 tritium-producing burnable absorber
rods (TPBARs) in WBN's reactor core. Irradiating the TPBARs in the
reactor core supports the U.S. Department of Energy (DOE) in
maintaining the nation's tritium inventory. TVA will insert the TPBARs
into positions in the reactor core where conventional burnable poison
rods would normally be (poison rods contain boron which reacts with
neutrons making them unavailable for interacting with uranium atoms,
thereby slowing fission and heat generation). TPBARs are not reactor
fuel and do not generate thermal energy for generating electrical
energy.
TPBARs use lithium rather than boron. Neutron irradiation in the
reactor core converts the lithium in the TPBARs into tritium. After one
operating cycle, TVA would remove the fuel assemblies containing TPBARs
from the WBN core and put them into the spent fuel pool. TVA would,
after several weeks (based on plant schedules rather than decay
considerations), remove the irradiated TPBARs from the fuel assemblies
and consolidate them into shipping casks for DOE to transport to its
tritium extraction facility at its Savannah River Site.
The proposed action is in accordance with the licensee's
application of August 20, 2001, as supplemented by letters of October
29, November 14, November 21, December 7, December 19, 2001, and
January 14, February 19, February 21, May 21, May 23, and July 30,
2002.
The Need for the Proposed Action
The proposed action would allow WBN to provide irradiation services
for DOE to maintain the nation's tritium supply as prescribed by Public
Law (Pub. L.) 106-65. Section 3134 of PL 106-65 directs the Secretary
of Energy to produce new tritium at TVA's Watts Bar power plant.
Environmental Impacts of the Proposed Action
DOE's Environmental Impact Statement, DOE/EIS-0288, Final
Environmental Impact Statement (EIS) for the Production of Tritium in a
Commercial Light Water Reactor, dated March 1999, assessed the
environmental impacts of producing tritium at WBN. TVA was a
cooperating Federal agency in preparing this EIS and adopted the EIS in
accordance with 40 CFR 1506.3(c) of the Council on Environmental
Quality regulations. DOE also prepared a Tritium Production Core (TPC)
Topical Report, NDP-98-181, Rev. 1, to address the safety and licensing
issues associated with incorporating TPBARs in a reference pressurized-
water reactor. The NRC used its Standard Review Plan (NUREG-0800) as
the basis for evaluating the impact of the TPBARs on a reference plant.
The NRC reviewed the TPC Topical Report and issued a Safety Evaluation
Report, NUREG-1672, in May 1999. NUREG-1672 identified 17 plant-
specific interface issues that a licensee would have to address in
support of a plant specific amendment to operate a tritium production
core. TVA's application of August 20, 2001, and supplements, addressed
these interface issues. NRC staff is reviewing TVA's amendment request
and will issue a safety evaluation documenting its review.
1. Radiological Impact from Tritium Release to the Reactor Coolant
System (RCS) Under Normal Plant Operations with 2304 TPBARs in the Core
Tritium levels in the RCSs of large pressurized-water reactors have
ranged as high as 4000 curies per year (Ci/yr) without exceeding
regulatory limits. TVA estimated, as discussed in its May 23, 2002,
letter, that the tritium level in the RCS at WBN would increase from
about 1826 Ci/yr to 3170 Ci/yr with 2304 TPBARs in the reactor. This
increased tritium level could increase overall occupational exposure,
but NRC data summarized in NUREG-0713, ``Occupational Radiation
Exposure at Commercial Nuclear Power Reactors and Other Facilities,''
dated 1995, indicate tritium exposure is not an important contributor
to overall occupational exposure.
TVA stated that WBN does not expect this increased activity to
affect normal RCS feed-and-bleed operation throughout the cycle, as
discussed in its May 23, 2002, letter. The NRC staff finds no reason to
disagree with TVA's conclusion. Thus, primary coolant discharge volumes
should be similar to current volumes.
The staff concludes that the additional dose rate from operating
WBN with 2304 TPBARs in the reactor will not have a significant impact
on TVA's ability to control worker radiation doses and keep them well
within regulatory limits using the controls and practices in WBN's
existing Radiation Protection Program.
If increased RCS feed and bleed is required, it may be necessary to
temporarily store the increased volume of tritiated liquid onsite, or
to dilute the tritiated liquid to ensure that 10 CFR part 20 discharge
limits are met. WBN has sufficient storage tanks to accommodate this
additional liquid waste.
2. Radiological Impact from Liquid Effluents Under Normal Plant
Operations with 2304 TPBARs in the Core
The WBN facility has waste-treatment systems designed to collect
and process waste that may contain radioactive material. The tritium in
liquid effluents from WBN is diluted to a relatively low
[[Page 54827]]
concentration before it reaches even the most highly exposed members of
the public. TVA's submittal of May 23, 2002, shows that the total
additional dose to the maximally-exposed members of the public within
50 miles of WBN from tritium in liquid effluents is estimated to be
0.01 millirem per year (mrem/yr). This total dose, considering the
minimal increase from tritium production, is less than 1.0 percent of
the NRC 3-mrem/yr guideline for effluent exposure to the public. The
staff concludes that the potential radiological impact on plant
workers, members of the public, and the environment from operation with
the TPC complies with all regulatory dose limits.
3. Radiological Impact from Radioactive Gaseous Emissions Under Normal
Plant Operations with 2304 TPBARs in the Core
A portion of the tritium might be released to the atmosphere. The
amount would depend on plant conditions and the manner in which TVA
operates WBN. Individuals could be exposed to tritium in a variety of
pathways if it was released to the atmosphere. These pathways include
inhalation and skin absorption, as well as consumption of meat,
vegetables and milk. According to TVA, in its submittal of May 23,
2002, the calculated tritium dose to the most highly-exposed members of
the public through all pathways would be about 63 percent of the NRC
annual exposure guideline for airborne effluents.
4. Radiological Impact from Solid Radioactive Waste Under Normal Plant
Operations with 2304 TPBARs in the Core
Irradiation of TPBARs is expected to increase the number of curies
and volume of solid radioactive waste, primarily because of disposal
(offsite) of the associated base plates and thimble plugs, which become
irradiated. The estimated increase in activity inventory is from
approximately 1800 Ci/year to approximately 3500 Ci/yr. The estimated
increase in volume is from 32,820 cubic feet/year to 32,853 cubic feet/
year. The estimated resultant total worker dose resulting from handling
the increased solid waste is approximately 1.1 percent of the dose
assessment estimate of record. Offsite shipment and disposal would be
in accordance with established agreements between TVA and DOE.
5. Radiological Impact to Workers in the Fuel Storage Area Under Normal
Plant Operations with 2304 TPBARs in the Core
The proposed amendment is not expected to significantly affect the
doses to the workers in the fuel storage area. The TPBARs are designed
to have minimal effect on plant operations, including refueling
operations. Unirradiated TPBARs will produce no increase in exposure,
occupational or public, because they are essentially non-radioactive.
Possible increases in tritium airborne activity may increase dose to
workers handling and consolidating radioactive TPBARs. However, TVA
stated, in its submittal of May 23, 2002, that WBN's station dose
assessment of record bounds the expected increase.
6. Non-Radiological Impact with 2304 TPBARs in the Core
The proposal does not affect non-radiological plant effluents. The
proposal does not result in any significant changes to land use or
water use. It also does not result in any significant changes to the
quantity or quality of effluents, and no effects on endangered or
threatened species or on their habitat are expected. Therefore, no
changes in, or different types of, non-radiological environmental
impacts are expected as a result of the amendment.
7. Radiological Impact from Postulated Accidents with 2304 TPBARs in
the Core
TVA's submittal of May 23, 2002, discussed the effects of TPBARs on
the possible consequences of the following postulated accidents
discussed in WBN's Updated Final Safety Analysis Report (UFSAR):
Fuel-handling accident
Design basis loss-of-coolant accident (LOCA)
Main steamline failure outside of containment
Steam generator tube rupture
Loss of normal alternating current power to plant
auxiliaries
Waste gas decay tank failure
Rod ejection accident
Failure of small lines carrying primary coolant outside
containment
Discussions of the postulated accidents with the greatest
radiological consequences appear below.
a. Fuel-Handling Accident
This accident is defined as dropping a spent fuel assembly
containing irradiated TPBARs resulting in rupture of the cladding on
all the fuel rods. TVA's calculations conservatively assumed that 24
TPBARs (the maximum possible number) are in the dropped spent fuel
assembly and that they all rupture and transfer their tritium to the
spent fuel pool. Releasing this activity to the (1) control room
boundary, (2) Exclusion Area Boundary over 2 hours, and (3) Low
Population Zone over 30 days results in the doses to the thyroid, skin
(beta), whole body (gamma), and Total Effective Dose Equivalent (TEDE),
as defined in 10 CFR part 20, that are small percentages of regulatory
limits.
b. LOCA
This accident is defined as losing reactor coolant at a rate in
excess of the capability of the reactor coolant makeup system. LOCAs
could occur from breaks in pipes in the reactor coolant pressure
boundary up to and including a break equivalent in size to the double-
ended rupture of the largest pipe in the RCS. TVA conservatively
assumed that the entire tritium content of the 2304 TPBARs is released
into containment during a postulated LOCA. Releasing this activity to
the (1) control room boundary, (2) Exclusion Area Boundary over 2
hours, and (3) Low Population Zone over 30 days results in doses to the
thyroid, skin (beta), whole body (gamma), and TEDE that are small
percentages of regulatory limits.
8. Post-LOCA Hydrogen Generation Inside Containment
TVA's submittal of August 20, 2001, stated that TPBARs could
release additional hydrogen to the containment following a large-break
LOCA (LBLOCA). WBN has emergency operating procedures in place to start
a hydrogen recombiner train when the containment volumetric percentage
of hydrogen reaches 3 percent. Previous analysis for a conventional
(non-TPBAR) core in the WBN UFSAR indicated that for an LBLOCA, with no
recombiners started, the containment hydrogen concentration reached
3.75 percent 4 days following event initiation. With additional
hydrogen from the TPBARs, TVA's analysis indicated that the containment
hydrogen concentration would only slightly increase 2 days following
event initiation. If one recombiner train is started 24 hours after
event initiation for the TPBAR core, the peak containment hydrogen
concentration is limited to less than 4 percent for up to 6 days.
Having up to 24 hours to place a recombiner train in service to
maintain the containment hydrogen concentration below 4 percent is
adequate in satisfying NRC Regulatory Guide 1.7. Accordingly, reactor
operation with the TPBARs will not be a significant contributor to the
post-LOCA hydrogen inventory, and will not
[[Page 54828]]
have a significant impact on the total hydrogen concentration within
the containment when compared to the values associated with the non-
TPBAR core. The maximum containment hydrogen concentration can be
maintained at less than the lower flammability limit of 4.0-volume-
percent, with one recombiner train started at a 3-percent hydrogen
concentration approximately 24 hours after an LBLOCA.
Summary
The Commission has completed its evaluation of the proposed action.
The proposed action will not significantly increase the probability or
consequences of accidents, no changes are being made in the types of
effluents that may be released offsite, and there is no significant
increase in occupational or public radiation exposure. Therefore, there
are no significant radiological environmental impacts associated with
the proposed action.
With regard to potential non-radiological impacts, the proposed
action does not have a potential to affect historic sites. It does not
affect non-radiological plant effluents and has no other environmental
impact. Therefore, there are no significant nonradiological
environmental impacts associated with the proposed action.
Environmental Impacts of the Alternatives to the Proposed Action
As an alternative to the proposed action, the staff considered
denial of the proposed action (i.e., the ``no-action'' alternative).
Denial of the application would result in no significant change in
current environmental impacts. However, because there are no
significant environmental impacts associated with this action, and
because Pub. L. 106-65 directs that DOE produce tritium at WBN or the
Sequoyah Nuclear Plant, this is not considered a viable option.
Alternative Use of Resources
DOE evaluated the action, including completing construction of one
or both of the Bellefonte Nuclear Plant Units and construction of an
accelerator facility at the Savannah River site and concluded that the
proposed alternative has the least environmental impact of the options
considered. The NRC has no reason to disagree with DOE's decision.
Agencies and Persons Consulted
On August 15, 2002, the staff consulted with the Tennessee State
official, Debra Schults of the Tennessee Bureau of Radiological Health,
regarding the environmental impact of the proposed action. The State
official had no comments.
Finding of No Significant Impact
On the basis of the environmental assessment, the NRC concludes
that the proposed action will not have a significant effect on the
quality of the human environment. Accordingly, the NRC has determined
not to prepare an environmental impact statement for the proposed
action.
For further details with respect to the proposed action, see the
licensee's letter dated August 20, 2001, as supplemented by letters
dated October 29, November 14, November 21, December 7, December 19,
2001, and January 14, February 19, February 21, May 21, May 23, and
July 30, 2002. Documents may be examined, and/or copied for a fee, at
the NRC's Public Document Room (PDR), located at One White Flint North,
11555 Rockville Pike (first floor), Rockville, Maryland. Publicly
available records will be accessible electronically from the Agencywide
Documents Access and Management System (ADAMS) Public Electronic
Reading Room on the internet at the NRC Web site, http://www.nrc.gov/
reading-rm/adams.html 
. Persons who do not have access to ADAMS or who
encounter problems in accessing the documents located in ADAMS, should
contact the NRC PDR Reference staff by telephone at 1-800-397-4209 or
301-415-4737, or by e-mail to pdr@nrc.gov.
Dated at Rockville, Maryland, this 20th day of August, 2002.
For the Nuclear Regulatory Commission,
L. Mark Padovan,
Project Manager, Section 2, Project Directorate II, Division of
Licensing Project Management, Office of Nuclear Reactor Regulation.
[FR Doc. 02-21644 Filed 8-23-02; 8:45 am]
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