ML20079K463
| ML20079K463 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/23/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20079K451 | List: |
| References | |
| NUDOCS 8301070503 | |
| Download: ML20079K463 (3) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 20 TO FACILITY OPERATING LICENSE DPR-77 AND AMENDMENT N0.10 TO FACILITY OPERATING LICENSE DPR-79 TENNESSEE VALLEY AUTHORITY INTRODUCTION On August 16, 1982, TVA requested a change to the Sequoyah Technical Specifications concerning maximum isolation time for the outboard containment isolation valve.
The change in the maximum allowable stroke time would be increased from 10 seconds to 20 seconds to permit the inboard isolation valves to close before the outboard isolation valves.
By letter dated August 16, 1982, TVA also proposed a change to the Sequoyah Units 1
.ar,d 2 Technical Specifications regarding testing of containment protective fuses.
TVA believes that the required testing of 10% of these fuses every 18 months is unnecessary.
The proposed change suggests visually inspecting at least 1C% of each fuse type.
EVALUATION t
The maximum isolation times for containment isolation valves are found in Table 3.6-2 of Sequoyah Units 1 and 2 Technical Specifications.
TVA has suggested increasing the maximum allowable stroke time of the outboard containment isolation valve (FCV-62-77) from 10 to 20 seconds.
The increased stroke time permits the.
inboard isolation valves (FCV-62-72, 73 or 74) to close before the outboard isola-tion valve.
This. sequence prevents overpressurizing the letdown line between the containment isolation valves and lifting the relief valve 62-662.
TVA's proposal is justified by a May 5,1982, letter from Darrell G. Eisenhut to All Licensees of Operating Plants, " Engineering Evaluation of the H.B. Robinson Reactor Coolant System Leak on January 29, 1981," which supports the TVA closing sequence since overpressurizing the relief valve would be prevented.
Additionally, the staff agrees that TVA's proposed order of containment isolation valve closing, i.e.
inboard prior to outboard, may decrease relief valve bellow failure.
Therefore,-
the maximum allowable stroke time of FCV-62-77 should be increased to 20 seconds.
At Sequoyah there are three types of protection fuses: 6900 and 480 volt fuses crimped inline and 480 volt fuses located in clip type holders.
The licensee has indicated in regard to these fuses that: a) removal and insertion of fuses located in clip type holders may damage the holder's contact points; b) due to the seismic design of the holders, fuse removal will destroy the fuse itself; c) removal and replacement of inline fuses may compromise cable integrity, and d) removal of fuses
'.that are crimped inline and wrapped with heat shrink insulation material will destroy the fuse itself.
83o1070503 821223 DR ADOCK 05000 b
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4 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 20 TO FACILITY OPERATING LICENSE-DPR-77 AND AMENDMENT NO.10 TO FACILIiY OPERATING LICENSE DPR-79 TENNESSEE VALLEY AUTHORITY INTRODUCTION 1
On August 16, 1982, TVA requested a change to the Sequoyah Technical Specifications concerning maximum isolation time for the outboard containment isolation valve.
The change in the maximun allowable stroke time would be increased from 10 seconds-to 20 seconds to pennit the inboard isolation valves to close before the outboard isolation valves.
By letter dated August 16, 1982 TVA also proposed a change to the Secuoyah Units 1 and 2 Technical Specifications regarding testing of containment protective fuses.
TVA believes that the required testing of 10% of these fuses every 18 months is unnecessary.
The proposed change suggests visually inspecting at least 10% of each fuse type.
EVALUATION The maximum isolation times for containment isolation valves are found in Table 3.6-2 of Sequoyah Units 1 and 2 Technical Specifications.
TVA has suggested increasing the maximum allowable stroke time of the outboard containment isolation-valve (FCV-62-77) from 10 to 20 seconds.
The increased stroke time permits the inboard isolation valves (FCV-62-72, 73 or 74) to close before the outboard isola-tion valve.
This sequence prevents overpressurizing the letdown line between the containment isolation valves and lifting the relief valve 62-662.
TVA's proposal is justified by a May 5,1982, letter from Darrell G. Eisenhut to All Licensees of Operating Plants, " Engineering Evaluation of the H.B. Robinson Reactor Coolant System Leak on January 29, 1981," which supports the TVA closing sequence since overpressurizing the relief valve would be prevented.
Additionally, the staff agrees that TVA's proposed order of containment isolation valve closing, i.e.
inboard prior to outboard, may decrease relief valve bellow failure.
Therefore, the naximum allowable stroke time of FCV-62-77 should be increased to 20 seconds.
At Sequoyah there are three types of protection fuses: 6900 and 480 volt fuses crimped inline and 480 volt fuses located in clip type holders.
The licensee-has indicated in regard to these fuses that: a) removal and insertion of fuses located in clip type holders may damage the holder's contact points; b) due to the seismic design of the holders, fuse removal will destroy the fuse itself; c) removal and replacement of inline fuses nay compromise cable integrity, and d) removal of fuses that are crimped inline and wrapped with heat shrink insulation material will destroy the fuse itself.
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. Due to inaccessibility, destructive removal is required for testing of fuses at the Sequoyah Plant; thus, the licensee has requested the subject surveillance requirement changed to require only visual inspection.
In justification of the change, the
' licensee has quoted Gould Shawmut, a major fuse manufacturer, to the effect that "Under no condition can a current limiting fuse ever become less protective over life."
Based on the above and the proposed periodic visual inspection, the. staff concludes that there is reasonable assurance that the fuses will perform their safety function over the next fuel cycle without perfoming the subject surveillance.
Therefore, interim Technical Specification relief is being granted for Sequoyah. Unit I until.
the completion of Cycle 2 as indicated through a Technical Specification amendment.
The proposed change for Sequoyah Unit 2 will be considered at a later date. of the August 16, 1982, letter deals with a typographical' error con--
tained in Table 4.4-5 involving the inadvertent interchange of vessel locations.
The staff agrees that the correction should be made 50 that the location of capsule 0
0 T is 40 and the location of capsule S is 4.
ENVIRONMENTAL CONSIDERATION We have detemined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any signif-icant environmental impact.
llaving made this determination, we have further con-cluded that the awndment involves an action which is insignificant from the stand-point of environmental impact and, pursuant to 10 CFR 51.5(d)(4), that an environ-mental impact statement or negative declaration and environmental impact appraisal' need not be prepared in connection with the issuance of this amendment.
4 CONCLUSION We have concluded, based on the considerations discussed above, that: (1)because the amendment does not involve a significant increase in the probability or con-sequences of accidents previously considered, does not create the possibility of an accident of a type different from any evaluated previously, and does not involve a significant decrease.in a safety margin, the amendment does not involve a l
significant hazards consideration, (2) there is reasonable assurance that the health I
and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regu-lations and the issuance of this amendment will not be inimical to the common defense j
and security or to the health and safety of the public.
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Date: December 23, 1982 Principal Contributors: Melanie Hiller, Licensing Branch No. 4,DL Carl Stahle. Licensing Branch No. 4 DL John Knox, PSB OFFICE) suname) om) l nne ronu sie nog uncu aa.o OFFICIAL RECORD COPY usopo mi-m.m