ML20059F304
| ML20059F304 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/03/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20059F297 | List: |
| References | |
| NUDOCS 9401130264 | |
| Download: ML20059F304 (3) | |
Text
- _ - _ _ _ - _ _ _ _
o UNITED STATES NUCLEAR REGULATORY COMMISSION
~
n
{
WASHINGTON, D. C. 20555 k... /
ENCLOSURE 3
+
i SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.175 TO FACILITY OPERATING LICENSE NO. DPR-77 AND AMENDMENT NO.166 TO FACILITY OPERATING LICENSE NO. DPR-79 i
TENNESSEE VALLEY AUTHORITY SE0U0YAH NUCLEAR PLANT. UNITS 1 AND 2 l
DOCKET N05. 50-327 AND 50-328
1.0 INTRODUCTION
By application dated June 16, 1993, and supplemented by letter dated November 10, 1993, the Tennessee Valley Authority (the licensee) proposed amendments to the Technical Specifications (TS) for Sequoyah Nuclear Plant (SQN) Units 1 and 2.
The requested changes would replace the maximum lifting forces specified for the ice condenser intermediate deck doors in Surveillance Requirement 4.6.5.3.2.b with values that were derived from a Westinghouse Electric Company analysis. The new values would be slightly higher than the present values specified in the TS, which would allow the lifting force l
specified for the intermediate deck doors to be slightly greater (less conservative) than the present value. The supplemental letter dated November 10, 1993, supplied information that corrected the assignments given the intermediate deck doors in the original submittal, but did not change the initial proposed no significant hazards consideration determination.
2.0 EVALUATION The containment ice condenser intermediate deck doors provide a barrier between the ice beds and the upper plenum of the ice condenser. They are closed during all modes of plant operation to minimize sublimation of ice that could occur from the entry of warm air, and can be opened for entry into the i
upper plenum for maintenance and inspections. During an accident that pressurizes the lower containment, these doors, along with the inlet and top deck doors of the ice condenser, open automatically by the forces created by the air flow to provide a flow path through the ice beds to the upper l
containment to control containment pressure.
The intermediate deck doors also prevent reverse flow of air from the upper compartment to the lower compartment. The surveillance requirement specifies the maximum lifting force that should be applied manually to a door to ensure that it is capable of promptly opening in the event of an accident that requires air flow through the ice beds.
9401130264 940103 l
PDR ADOCK 05000327 P
i 1 l The lifting forces required to perform the surveillance are as follows:
DAQE PRESENT TS VALUES PROPOSED NEW VALUES 0-1, 0-5 s 33 lbs.
s 37.4 lbs 0-2, 0-6 s 30 lbs.
s 33.8 lbs.
0-3, 0-7 s 28 lbs.
s 31.0 lbs.
0-4, 0-8 s 28 lbs.
s 31.8 lbs.
A Westinghouse Electric Corporation analysis supplied to SQN in 1976 indicated that the specified lifting forces were based on factory testing of production doors. These tests indicated that the proper values should be those indicated above in the " Proposed New Values" column.
However, when the TS were generated, the lower values indicated in the "Present TS Values" column were incorporated. A study by Westinghouse has been unable to determine the source of the lower values.
Since the present forces specified in the TS were 3 to 4.4 lbs. lower than necessary, SQN has experienced occasions when a lifting force was found to be too close to the TS limit, necessitating additional maintenance and testing.
The original values supplied by Westinghouse are used at other ice condenser plants and were verified to be the values used in the SQN design basis accident analysis performed by Westinghouse.
Based on the staff's evaluation of the information supplied by the licensee, I
the analysis performed by Westinghouse that determined the proper maximum lifting forces, and the use of these forces in the accident analysis, the staff agrees that use of the new values for the surveillance requirement is appropriate. The safety analysis corresponding to the operation of the doors is not affected, and the potential for introducing unwarranted operability concerns and maintenance activities is reduced.
Therefore, the proposed TS change is satisfactory.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Tennessee State official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendments change a surveillance requirement. 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 (58 FR 41513). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
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.
- l
5.0 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 comon defense and security or to the health and safety of the public.
Principal Contributor: David E. LaBarge Dated:
January 3, 1994 i
e
,,c v
,,,_,.,y.
.,.,,~m,.v.-cmy.s