ML20211B975
| ML20211B975 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 02/12/1987 |
| From: | Youngblood B Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20211B973 | List: |
| References | |
| NUDOCS 8702190647 | |
| Download: ML20211B975 (5) | |
Text
e 7590-01 UNITED STATES NUCLEAR REGULATORY COMMISSION
+
TENNESSEE VALLEY AUTHORITY DOCKET NOS. 50-327 AND 50-328 ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT The U. S. Nuclear Regulatory Connission (the Commission) is considering issuance of an exemption from 10 CFR 50, Appendix J. General Design Criteria 55 - Reactor Coolant Pump Seal Injection Lines to the Tennessee Valley Authority, (the licensee) for the Sequoyah Nuclear Plant, Units 1 and 2, located at the licensee's site in Hamilton County, Tennessee. The exemption was requested by the licensee by letter dated January 23, 1987.
ENVIRONMENTAL ASSESSMENT Identification of Proposed Action: The exemption will permit the reactor coolant pressure boundary isolation on the reactor coolant pump seal injection lines to be provided by in-containment check valves and out-of-containment manual isolation valves. General Design Criteria (GDC) 55 requires that each line that is part of the reactor coolant pressure boundary and that penetrates primary reactor containment shall be provided with containment isolation valves.
The combination of valves, automatic or locked closed, inside and outside containment is specified in GDC 55 unless it can be demonstrated that the con-tainment isolation provisions for a specific loss of lines are acceptable on some other defined basis.
The reactor coolant pump seal injection was designed to provide continued seal water during operation and following certain transients and accidents. The seal injection line was not designed, therefore, to be automatically isolated by an isolation signal. GDC 55 also requires that valves outside containment
[ nan P
be located close to the containment and other appropriate requirements be pro-vided to minimize the probability or consequences of an accidental rupture of i
the lines.
)
In support of the exemption, the licensee has proposed that redundant containment isolation is provided by the check valves inside containment, and by redesigned local manual valves outside containment. The seal injection is a closed system and the charging pumps provide a water seal to prevent the release of containment atmosphere to the environment. Any leaks are into leak collection systems which are designed to handle leaks and contaminated fluids greater than expected from the seal injection system.
The Need for the Proposed Action: The proposed exemption is needed to permit the licensee to operate the plant without being in violation of the Commission's ,
requirements.
Environmental Impact of the Proposed Action: The proposed exemption is from the specified combination of valves in GDC 55. The need for automatic isolation is to insure that the containment atmosphere is not released to the environment following an accident. For the seal injection line, however, continued operation following certain transients and accidents does not require automatic isolation on a containment isolation signal. The seal injection system is a closed system outside containment and was designed and is operated to prevent offsite releases in nonnal operation or following accidents. However, should the seal injection be discontinued and the check valve inside containment leak, it would be into a closed system which is not open to the environment. The licensee has procedures if the need arises which would further prevent any containment atmosphere release possibility.
F For a line' rupture or valve leak outside containment, the seal injection line is located in controlled areas where leakage is collected in the Tritiated Drain Collection Tank. The drains are sized to accommodate a maximum leak rate of 50 gpm that would be expected from a Residual Heat Removal pump shaft seal.
The consequences of a leak this size have been evaluated and the analysis was previously found acceptable. A leak from the seal injection line which would release containment atmosphere in this area is within the 50 gom analysis al-ready found acceptable. Because of this, there would be a negligble effect on the overall risk from plant operation. In addition, since any leak would be into a closed system, there would not be any leakage, either radioactive or non-radioactive, to the environment. Therefore, in consideration of all of the above, the exemption does not involve a signficant environmental impact.
Alternative to the Proposed Action: Because the staff has concluded that there is no significant impact associated with the proposed exemption, any alternative to the exemption will have either no environmental impact or greater environmental impact. In further support of this, the licensee investigated the alternative of installing automatic isolation valves and improving the leak detection capa-bilities in the seal injection lines and areas respectively. The engineering costs would be !!.500,000 minimum with valves and supplies from stock or ware-housed, and the exposure to installation crews during an cutage is estimated to be about 47 man-rem. This alterrative may reduce the effects of a line rupture or valve leak somewhat but would result in increased radiation exposure and cost.
Alternative Use of Resources: This action does rot involve the use of resources not previously considereo in connection with the " Final Envirentrental Statement Related to the Operation of Sequoyah fluclear Plant, Units 1 and 2." dated July 1974
e 4-Agencies and Persons Consulted: The NRC staff reviewed the licensee's request that supports the proposed exemption. The NRC staff did not consult other agencies or persons.
FINDING OF NO SIGNIFICANT IMPACT The Coninission has detennined not to prepare an environmental impact statement for the proposed exemption.
Based upon the 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 request for exemption dated January 23, 1987, which is available for public inspection at the Commission's Public Document Room,1717 H Street, N. W., Washington, D. C. ,
and at the Chattanooga-Hamilton County Bicentennial Library, 1001 Broad Street, Chattanooga, Tennessee 37401.
Dated at Bethesda, Maryland, this 12*h day of February 1987.
FOR THE UCLEAR REGULATORY COMMISSION B. 5 Yo gblood, frector PW Proj ct Directorate #4 Divisio of PWR Licensing-A Office of Nuclear Reactor Regulation
_ - - ____.._.-,__,m-__-.. ., - _ _ . . _ _
...r.__ _ -_ , _ _ _ - _ . - - . _ _ -
Mr.-S.A. White Tennessee Valley Authority Sequoyah Nuclear Plant cc:
Tennessee Department of Public Reofonal Administrator, Region II Health U.S. Nuclear Regulatory Comission, ATTN: Director, Bureau of 101 Marietta Street, fl.W. , Suite 2900 Environtiental Health Services Atlanta, Georgia 30323 Cordell ifull Building h hville, Tennessee 37219 R. W. Cantrell ATTil: D.L. Williams Mr. Michael H. Mobley, Director Tennessee Valley Authority Division of Radiological Health 400 West Sunanit Hill Drive, W12 A12 T.E.R.R.A. Building Knoxville, Tennessee 37902 150 9th Avenue North flashville, Tennessee 37203 Mr. Bob Faas Westinghouse Electric Corp. County Judge P.O. Box 355 Hamilton County Courthouse Pittsburgh, Pennsylvania 15230 Chattanooga, Tennessee 37402 ,
\ R. L. Gridley
\i Tennessee Valley Authority 5N 157B Lookout Place Chattanooga, Tennessee 37402-2801 M. R. Harding i
Tennessee Valley Authority
' Sequoyah Nuclear Plant P.O. Box 2000 Soddy Daisy, Tennessee 37379 Resident Inspector /Sequoyah flPS c/o U.S. Nuclear Regulatory Comission 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 li.L. Abercrombie Tennessee Valley Authority Seouoyah flucicar Plant P.O. Box 2000 Soddy Daisy, Tennessee 37379