ML20039D676
| ML20039D676 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 12/17/1981 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Parris H TENNESSEE VALLEY AUTHORITY |
| Shared Package | |
| ML20039D677 | List: |
| References | |
| TASK-2.E.4.2, TASK-TM TAC-10187, NUDOCS 8201050431 | |
| Download: ML20039D676 (6) | |
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DISTRIBUTION Docket Files NRC PDR L PDR TERA Docket Nos. 50-259 NSIC P-JJ 50-260
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Mr. Hugh G. Parris ACRS-10 Manager of Power RClark 1-' "iSF Tennessee Valley Authority SNorris
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Chattanooga, Tennessee 37401 E.tceer O. Sku wt
Dear llr. Parris:
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SUBJECT:
CONTAINMENT PURGING DURING NOR!!AL OPERATIO!1 AND STATUS AND COMPLETION OF TMI ITEf1 II.E.4.2.5 In our letter of November 29, 1978, we identified the generic concerns of purging and venting of containments to all operating reactor licensees and requested your response to these concerns. Our review of your response was interrupted by the TitI accident and its demands on staff resources.
Consequently, as you know, an Interim Position on containment purging and venting was transmitted.to you on October 22, 1979. You were requested to implement short-tem corrective actions to remain in effect pending completion of our longer-tem review of your response to our November 29, 1978 letter.
Over the past several months we and our contractors have been reviewing the responses to our November 1978 letter to close out our long-tem review of this rather complex issue. The components of this review are as follows:
1.
Confomance to Standai-d Review Plan Section 6.2.4 Revision 1 and Branch Technical Position CSD 6-4 Revision 1.
These documents were provided as enclosures to our Novalber 1978
' '.ter.
2.
Valve Operability.
Although the Interim Position allowed blocking of the valves at partial-open positions, this is indeed an interim position. Earlier we requested a program demonstrating operability of,the valves in accordance with our " Guidelines for Demonstrative Operability of Purge and Vent Valves." These Guidelines were sent to you in our letter of September 27, 1979.
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3.
Safety Actuation Signal Override This involves the review of safety actuation signal circuits to ensure that overriding of one safety actuation signal does not also cause the bypass of any other safety actuation signal.
4.
Containment Leakage Due to Seal Deterioration Position B.4 of the BTP CSB 6-4 requires that provisions be made to test the availability of. the isolation function and the leakage rate of the isolation valves in the vent and purge lines, individ-ually, during reactor operations. But CSB 6-4 does not explain when or how these tests are to be performed. Enclosure 1 is an amplification of Position B.4 concerning these tests.
The status of our long-tem review of the above items for the Browns Ferry Nuclear Plant is as follows:
1.
Conformance to Standard Review Plan Section 6.2.4 Revision 1 and Branc?. Technical Position CSB 6-4 Revision 1 4
We have completed our review of the infomation provided in your responses of December 21,1978; March 1, Jude 12 November 13, November 14, December 10,1979 March 17, April 7. November 19, December 23,1980 (on NOREG-0737), April 22, June 2, and August 10, 1981. Attached as Enclosure 2 is our Safety Evaluation. We have concluded that the containment vent and purge system at Browns Ferry meets the criteria in NRC Standard Review Plan (SRP) 6.2.4, Revision 1 and the associated Branch Technical Position (BTP)
CSB 6-4, Revision 1, except for the following unresolved issues:
a.
Inclusion of a requirement in the Technical Specification to periodically tesc that the large butterfly valves meet the 2.5 second closure time in your letter of June 2,1981.
b.
Environmental qualification of the isolation valves and associated controls. Our review of this issue has not been completed; the review will be done as part of our review of your detailed response to JE Bulletin 79-Olb.
In the attached Safety Evaluation we also conclude that the Browns Ferry Nuclear Plant is in conformana. with position 5 i
of TMI-2 Action Plan requirement II.E.4.2 as set forth in NUREG-0737.
2.
Valve Operability Our review of this issue is nearing completion. You will be advised separately of the results of our evaluation.
3.
Safety Actuation Signal Override "la h *: un enmnlstad nm, v.au f m f*n s'i h e.. e S
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aspects of our long-tem review of this generic task is complete.
It is noted that a somewhat parallel review of engineered safety features reset is being carried out in conjunction with IAE Bulletin 80-06. That review will be handled separately outside the framework of the purge and vent review.
4.
Containment Leakage Due to Seal Deterioration We request that you propose a Technical Specification change incorporating the test requirements together with the details of your proposed test program within 60 days of receipt of this letter.
In closing, you my have noted the similarity of this long-tem generic issue with Item II.E.4.2 of NUREG-0737, TMI Action Plan. Except for Posttions 6 & 7 of Item II.E.4.2, the review of the other positions of Item II.E.4.2 have hen completed by this purge and vent review.
Your assistance in completing the outstanding purge and vent items, noted above, is also necessary to complete Item II.E.4.2.
Although the Technical Specifications necessary to finalize the purge and vent part of Item II.E.4.2 are not completely finalized, a recently developed sample Technical Specification is provided for your consideration as Enclosure 4.
We request that you review existing Technical Specifications (TSs) against the samp6e provided herein. For any areas in which your existing TSs needs expansion, you are requested to provide a TS change request within 60 days of receipt of this letter.
Please contact your NRC Project Manager should you have any questions.
The request for infomation and changes to the Technical Specifications contained in this letter are specific to the Browns Ferry Nuclear Plant.
Therefore, OMB clearance is not required under P.L.96-511.
Sincerely, i
I Thomas A. Ippolito, Chief l
Operating Reactors Branch #2 l
Division of Licensing l
Enclosures:
Distribution:
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H. S. Sanger, Jr., Esquire General Counsel Tennessee Valley Authority 400 Canmerce Avenue
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E llB 33 C Knoxville, Tennessee 37902 Mr. Ron Rogers Tennessee Valley Authority 400 Chestnut Street, Tower II-Chattanooga, Tennessee 37401 Mr. H. N. Culver 249A HBD 400 Commerce Avenue-Tennessee Valley Authority Knoxville, Tennessee 37902 Robert F. Sullivan U. S. Nuclear Regulatory Commission Route 2, Box 311 Athens, Alabama 35611 Athens Public Library South and Forrest Athens, Alabama 35611 Mr. John F. Cox Tennessee Valley Authority l~
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- 400 Ccamerce Avenue Knoxville, Tennessee 37902 Mr.' Herbert Abercrombie
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Tennessee Valley Authority l
P. O. Box 2000 Decatur, Alabara 35602 l
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i ENCLOSURE 1 i
PURGE / VENT VALVE LEAKAGE TESTS 4
The long term resolution of Generic Issue B-24, " Containment Purging During Normal Plant Operation," includes, in cart, the implementation of Item B.4 of Branch Technical Position (BTP) CSB 6-4.
Item B.4 specifies that provisions should be made for leakage rate testing of the (purge / vent system) isolation valves, individually, during reactor operation. Al though Item 3.4 does not address the testing frequency, Appendix J to 10 CFR Part 50 specifies a maximum test interval of 2 years.
As a result of the numerous reports on unsatisfactory performance of the resilient seats for the isolation valves in containment purge and vent lines (addressed in OIE Circular 77-11, dated September 6,1977), Generic Issue B-20, " Containment Leakage Due to Seal Deterioration," was established to evaluate the matter and establish an appropriate testing frequency for the
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isolation valves. Excessive leakage past the resilient seats of isolation valves in purge / vent lines is typically caused by severe environmental con-ditions and/or wear due to frequent use. Consequently, the leakage test frequency for these valves should be keyed to the occurrence of severe environ-mental conditions and the use of the valves, rather than the current require-ments of 10 CFR 50, Appendix J.
It is recommended that the following provision be added to the Technical Specifications for the leak testing of purge / vent line isolation valves:
" Leakage integrity tests shall be performed on the containment isolation valves with resilient material seals in (a) active purge / vent systems (i.e., those which may be. cperated during plant operating Modes 1 through 4) at least once every three months and (b) passive purge systems (i.e., those which must be administratively controlled closed during reactor operating Modes 1 through 4) at least once every six months."
By way of clarification, the above proposed surveillance specification is predicated on our expectation that a plant would have a need to go to cold shutdown several times a year. To cover the possibility that this may not occur, a maximum test interval of 6 months is specified. However, it is not our intent to require a plant to shutdown just to conduct the valve leakage integrity tests. If licensees anticipate long duration power oper-ations with infrequent shutdown, then installation of a leak test connection This that is accessible from outside containment may be appropriate.
It will not be will permit simultaneous testing of the redundant valves.
possible to satisfy explicitly the guidance of Item B.4 of BTP CSB 6-4 (which states that valves should be tested individually), but at least some testing of the valves during reactor operation will be possible.
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I It is intended that the above proposed surveillance specification be applied i
e., the to the active purge / vent lines, as well as passive purge lines:
purge lines that are administratively controlled closed during reactor oper-ating modes 1-4.
The reason for including the passive purge lines is that 3-20 is concerned wtih the potential adverse effect of. seasonal weather con-ditions on the integrity of the isolation valves. Consequently, passive purge lines must also be included in the surveillance program.
The purpose of the leakage integrity tests of the isolation valves in the containment purge and vent lines is to identify excessive degradation of the resilient seats for these valves. Therefore, they need not be conducted with the precision required for the Type C isolation valve tests in 10 CFR These tests would be performed in addition to the Part 50, Appendix J.
quantitative Type C tests required by Appendix J and would not reliev In view of the wide variety of valve types and seating materials, the acceptance criteria for such tests should be developed on a plant-specific basis.
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