ML20058A102
| ML20058A102 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 11/09/1993 |
| From: | Hebdon F Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20058A105 | List: |
| References | |
| NUDOCS 9311300105 | |
| Download: ML20058A102 (5) | |
Text
e UNITED STATES NUCLEAR REGULATORY COMMISSION TENNESSEE VALLEY AUTHORITY SE000YAH NUCLEAR PLANT. UNIT 2 DOCKET N0. 50-328 ENVIRONMENTAL ASSESSMENT AND FINDING 0F N0 SIGNIFICANT IMPACT Tte U.S. Nuclear Regulatory Commission (the Commission) is considering issuan:e of an 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 September 27, 1993.
ENVIRONMENTAL ASSESSMENT Identification of ProDosed 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 less than 1 month after the 2-year
' period ends.
On March 15, 1992, SQN Unit 2 started the Cycle 5 refueling outage. All j
Type B and Type C local leak rate tests were performed during the outage and the unit was returned to service on May 17, 1992.
Between March 1, 1993, and 1
9311300105 931109 PDR ADOCK 05000328 D
PDR l
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October 19, 1993, Unit 2 was in shutdown because of a steam leak in the secondary system. Due to the length of the shutdown, TVA has delayed the start of the Unit 2 Cycle 6 refueling outage to April 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.
To perform the tests in accordance with the requirement would force the unit to shut down in March 1994. To prevent this, the proposed exemption would allow a one-time deferment of the Appendix J interval requirement from March 15, 1994 until the shutdown in April 1994, a total of approximately 18 days.
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 April 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 18 days 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:
4.
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3 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 Types 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 80 percent of the 0.6 percent La limit, the remaining margin is sufficient to ensure any incremental increase in leakage resulting.
from the extensicn 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 (M0 VATS) of containment isolation valves, provide increased assurance that these components will perform their safety function associated with.
containment leakage.
3.
Many of the components'for which the exemption is requested were ir cluded 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.
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4 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.
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5 Acencies 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 sigrificant effect on the quality of the human environment.
For details with respect to this action, see the licensee's request for an exemption dated September 27, 1993, which is available for public inspection at the Commission's Public Document Room, Gelman Building, 2120 L Street, N.W., Washington, D.C., and at the Chattanooga-Hamilton County Library, 1101 Broad Street, Chattanooga, Tennessee 37402.
Dated at Rockville, Maryland, this 9th day of November 1993.
FOR THE NUCLEAR REGULATORY COMMISSION a
Frederick J. Heb on, Director Project Directorate 11-4 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation