[Federal Register Volume 59, Number 49 (Monday, March 14, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-5828]
[[Page Unknown]]
[Federal Register: March 14, 1994]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-328]
Tennessee Valley Authority; Sequoyah Nuclear Plant, Unit 2;
Environmental Assessment and Finding of No Significant Impact
The U.S. Nuclear Regulatory Commission (the Commission) is
considering issuance of a one-time schedular exemption from the
requirements of sections III.D.2(a) and III.D.3 of appendix J to 10 CFR
part 50 to the Tennessee Valley Authority, licensee for the Sequoyah
Nuclear Plant (SQN), Unit 2. The plant is located at the licensee's
site in Hamilton County, Tennessee. The exemption was requested by the
licensee in its letter dated February 4, 1994.
Environmental Assessment
Identification of Proposed Action
The action would exempt the licensee from the provisions in
sections III.D.2(a) and III.D.3 of appendix J to 10 CFR part 50 with
respect to the requirement to perform Primary Containment Type B and
Type C local leak rate tests at intervals no greater than 2 years. The
exemption would affect Unit 2 only and allow the tests to be delayed
until the Cycle 6 refueling outage. This outage is scheduled to start
approximately 4 months after the 2-year period ends.
Between March and April 1992, all Type B and Type C local leak rate
tests were preformed during the SQN Unit 2 Cycle 5 refueling outage.
Between March 1, 1993, and October 19, 1993, Unit 2 was shut down due
to a steam leak in the secondary system, and experienced several forced
shutdowns since it was restarted. Due to the accumulated length of the
shutdowns, TVA has decided to delay start of the Unit 2 Cycle 6
refueling outage until July 1994. As a result, the expiration of the 2-
year time interval for the Type B and Type C tests occurs before the
outage starts. Therefore, to perform the tests in accordance with the
requirement would force the unit to shut down in April 1994. To prevent
this, the proposed exemption would allow a one-time deferment of the
Appendix J interval requirement from March 1994 until the shutdown in
July 1994. The result would be an interval of approximately 4 months
since the previous test for any component.
This environmental assessment is similar to an environmental
assessment processed by the Commission and forwarded by letter dated
November 9, 1993. It was published in the Federal Register on November
16, 1993 (58 FR 60470). This action addressed the 10 CFR part 50
appendix J exemption for the Unit 2 refueling outage when it was
scheduled to begin in April 1994.
The Need for the Proposed Action
The proposed action is required to exempt the licensee from the
requirement to conduct Type B and Type C containment local leak rate
tests on SQN Unit 2 at a 2-year frequency so that the tests can be
performed during the Cycle 6 refueling outage that is scheduled to
start in July 1994.
Environmental Impacts of the Proposed Action
With respect to the requested action, exemption from the above
requirement would allow the licensee to delay conducting Type B and
Type C local leak rate tests at Unit 2 approximately 4 months beyond
the scheduled expiration date of the 2-year period. This relatively
small increase in the test interval does not significantly contribute
to the total Type B and Type C leakage limits.
The intent of Sections III.D.2(a) and III.D.3 of appendix J is to
ensure that containment leakage is maintained within the prescribed
limits. Based on the following information, the exemption will not
significantly affect the ability of the individual primary containment
components that are subject to Type B or Type C tests to perform this
safety function:
1. The valves and components for which the extension of the 2-year
interval is being requested have a history of being leak tight and in
good condition. The leak-tight condition of these components was last
verified by Type B and C local leak rate tests conducted during the
Cycle 5 refueling outage in 1992 and, at least for many, by the Type A
containment leak rate test conducted on Unit 2 during the same
refueling outage. Based on the present containment leakage that
accounts for the less than 8.0 percent of the 0.6 percent La limit, the
remaining margin is sufficient to ensure any incremental increase in
leakage resulting from the extension would not cause unacceptable as-
found test results.
2. Based on historical data, any incremental increase in leakage
because of the extension will be small. Improved maintenance practices
implemented during the Unit 2 Cycle 5 outage, including motor operated
valve testing of containment isolation valves, periodic replacement of
valve packing, and periodic lubrication of valve stems, provide
increased assurance that these components will perform their safety
function.
3. Many of the components for which the exemption is requested were
included in the Type A test performed in April 1992. This test
indicated a containment leak rate of 0.15 percent per day, which is
below the 0.1875 percent per day limit.
With regard to other potential radiological environmental impacts,
the proposed exemption does not increase the radiological effluents
from the facility and does not increase the occupational exposure at
the facility. Therefore, the Commission concludes that there are no
significant radiological impacts associated with the proposed
exemption.
With regard to potential nonradiological environmental impacts, the
proposed exemption involves systems located within the restricted areas
as defined in 10 CFR part 20. It does not affect nonradiological plant
effluents and has no other significant nonradiological environmental
impacts associated with the proposed exemption.
Therefore, the proposed exemption does not significantly change the
conclusions in the licensee's ``Final Environmental Statement Related
to the Operation of Sequoyah Nuclear Plant Units 1 and 2'' (FES), dated
February 21, 1974. The Commission concluded that operation of the
Sequoyah units will not result in any environmental impacts other than
those evaluated in the FES and its letter to the licensee dated
September 15, 1981, which granted the facility operating license DPR-79
for Unit 2.
Alternative to the Proposed Action
Because the staff has concluded that there is no measurable
environmental impact associated with the proposed exemption, any
alternative to this exemption will have either no significantly
different environmental impact or greater environmental impact.
The principal alternative would be to deny the requested exemption.
This would not reduce environmental impacts as a result of plant
operations.
Alternative Use of Resources
This action does not involve the use of resources not previously
considered in connection with the ``Final Environmental Statement
Related to the Operation of the Sequoyah Nuclear Plant, Units 1 and
2,'' dated February 21, 1974.
Agencies and Persons Consulted
The NRC staff has reviewed the licensee's request. The staff did
not consult other agencies or persons.
Finding of No Significant Impact
The Commission has determined not to prepare an environmental
impact statement for the proposed exemption.
Based upon the foregoing environmental assessment, we conclude that
the proposed action will not have a significant effect on the quality
of the human environment.
For details with respect to this action, see the licensee's request
for an exemption dated February 4, 1994, which is available for public
inspection at the Commission's Public Document Room, Gelman Building,
2120 L Street NW., Washington, DC, and at the Chattanooga-Hamilton
County Library, 1101 Broad Street, Chattanooga, Tennessee 37402.
Dated at Rockville, Maryland, this 7th day of March 1994.
For the Nuclear Regulatory Commission.
Frederick J. Hebdon,
Director, Project Directorate II-4, Division of Reactor Projects--I/II,
Office of Nuclear Reactor Regulation.
[FR Doc. 94-5828 Filed 3-11-94; 8:45 am]
BILLING CODE 7590-01-M
