ML20039H019
| ML20039H019 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 12/15/1981 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Jackie Jones CAROLINA POWER & LIGHT CO. |
| Shared Package | |
| ML20039H020 | List: |
| References | |
| TASK-2.E.4.2, TASK-TM NUDOCS 8201190431 | |
| Download: ML20039H019 (7) | |
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Docket No. 50-325 50-324 DEC 15 1981 N'/
h p~.m Mr. J. A. Jones
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i Senior E>ecutive Vice President 7'
Carolina Power a Light Cw.pany Cil DEC 2 21331>
336 Fayetteville Street j
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Raleigh, North Carolina 27502 Q
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Dear Mr. Jones:
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In our letter of November 29, 1978, we identified the generic clince'rns f 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 TNI accident and its demands on staff resources.
Consequently, as you know, an Interin Position on containment purging and venting was transmitted to you on October 22, 1979. You were requested to ir.plement short-tern corrective actions to remain in effect pending completion of our longer-term 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-term review of this rather complex issue. The components of this review are as follows:
1.
Conformance to Standard Review Plan Section 6.2.4 Revision 1 and Branch Technical Position CSB 6-4 Revision 1.
These documents were provided as enclosures to our November 1978 Tetter.
2.
Valve Operability Although the Interin 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. There is an acceptable alternative which you may wish to consider in lieu of completing the valve qualification program for the large butterfly-type valves. This would be the installation of a fully-qualified nini-purge system with valves 8-inches or smaller to bypass the larger valves. Such a system change mitjht prove more tinely and more sost-effective. The-system would neet BTP CSB 6-4 iten B.l.c.
3.
Safety Actuation Sional Override This involves the review of safety actuation signal circuits to en-sure that overridino of one safety actuation sianal does not also canse the bypass of any oth(r safety actbation signal omcq
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. 4. CContainment Leakage Due to Seal Deterioration Position D.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, indifidually, during reactor operations. But CSB 6-4 does not explain when or how these tests are to be perfomed. is an amplification of Position B.4 concerning these tests.
The status of our long-tem review of the above items for the Brunswick facil-ity is as follows:
1.
Confomance to Standa_rd Review Plan Section 6.2.4 Revision 1 and Branch Technical Position CSC 6-4iRevision 1.
This item is still under review. Since it appears that there may be some misunderstanding regarding the use of containment purge /
vent valves, a restatement of salient features of the position as i
interpreted by the staff is provided in Enclosure 2 to assist ycu in understanding subsequent correspondence on this item from the sta ff. is s draft Safety Evaluation Report (SER) for contain-ment venting and purging during normal operation which is provided for your information. Please note that the draft SER concludes you have not provided sufficient infomation for us to detemine that isolation valve closure will not be prevented by debris which could potentially become entrained in the escaping air and steam. One way of assuring that debris will not present a problem in this respect would be to install debris screens upstream of each inboard isolation valve as discussed in the draft SER.
In addition, the draft SER recommends that you propose a Technical Specification change to further reduce the possiblity of damage to the Standby Gas Treatment (SBGT) System during venting operations. Please submit an analysis that demonstrates debris entrainment cannot prevent isolation valve closure, and a proposed Technical Specification change as described in the draft SER within 90 days of receipt of this letter.
2.
Valve Operability Act50n on this iten cannot begin until we rective your valve operability analysis. We understand that this analysis is under-going internal review and will be submitted in the near future.
3.
Safety Actuation Signal Override Our SER for this item was forwarded by our letter dated August 26, 1981. We are expecting your response to our August 26, 1981 letter no later than early January 1932.
4.
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Containment Leakane Due to Seal Deterioration If the results of past and present surveillances are believed to 4
demonstrate operability of the subject valves, provide this infor-mation as justification.for not increa. Ting surveillance requirements 3
beyond that now required.
Provide this information.or proposed Technical Specifications, within 90 days of receipt of this letter.
4.
Containment Isolation Pressure Setpoint Our SER for this item (TMI Action Item II.E.4.2 Position 5) was fonwarded under our letter dated August 26, 1981. We consider 6
i this item complete for your facility.
f In closing, you nay have noted the similarity of this long-term generic issue with Item II.E.4.2 of NUREG-0737. TMI Action Plan. Except for Posi-i tions 6 and 7 of Item II.E.4.2, the review of the remaining outstanding j
positions of Item II.E.4..' will be completed by this purge and vent review.
Oureschedule of the purge and vent review agrees with the schedule for Item II.E.4.2.
Thus, your assistance in completing the outstanding purge and vent items, noted above, is necessary to complete Item II.E.4.2.
Although the Technical Specifi-I cations necessary to finalize the purge and vent part of Item II.E.$.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 against the sample provided herein.
For any
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areas in which your existing Technical Specifications need expansion, you are requestcJ to provide an appropriate change request within 90 days of receipt of this letter.
OM3 Clearance is not required for this request since it is being transmitted to nine or fewer addresses.
Please contact your NRC Project Manager should you have any questions.
Sincerely, Drfginal Sig,*d b)f L r. A. appor,to Thomas A. Ippolito, Chief Operating Reactors Branbh #2 j
Division of Licensing
Enclosures:
As stated J. Heltenes, AE0D NSIC cc: See next page T. Ippolito TERA S. Norrh ACRS (10) l DISTRIBUTION Local PDR J. Van Vliet f/w Docket File ORB #2 Rdg.
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Richard E. Jones, Esquire Carolina Power & Light Company 336 Fayetteville Street Raleigh, North Carolina 27602 George F. Trowbridge, Esquire Shaw, Pittman, Potts & Trowbridge 1800 M Street, N. W.
Washington, D. C.
20036 Resident Inspector U. S. Nuclear Regula. tory Cotmission P. O. Box 1057 Southport, North Carolina 28461 Southport - Brunswick County Library 109 W. Moore Street Southport, North Carolina 28461
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Mr. Charles R. Dietz Plant Manager P. O. Box 458 Southport, North Carolina 28461 r
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Enclo e e 1
? URGE / VENT VALVE LEAKAGE TESTS j
The long tem resolution of Generic Issue B-24, " Containment Purging During Normal Plant Operation," includes, in part, the implementation of Item B.4 of Branch Technics:1 Position (BTP) CSB 6-4 Item B.4 specifies that provisions should be made for leakage rate testing of the (purge / vent Al though system) isolation valves, individually, during reactor operation.
Item B.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 parformance of the resilient seats for the isolation valves in containment purge and vent lines (addressed in DIE Circular 77-11, dated September 6,1977), Generic Issue B-20 " Containment Leakage Due to Seal Deterioraticn," was established to evaluate the matter and establish an appropriate testing frequency for the Excessive leakage past the resilient seats of isolation isolation valves.
valves in purge / vent lines is typically caused by severe environmental con-Consequently, the leakage test ditions and/or wear due to frequent use.
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 T'echnical Specifications for the leak testing of purge / vent line isolation valves:
" Leakage integrity tests shall be perfomed on the containment isolation valves with resilient material seals in (a) active purge / vent systems (i.e., those which may be operated during plant operating Modes 1 through 4) at least once every three r0rths 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 preposed surveillance specification is predicated on our expectation that a plant woeld have a need to go to cold To cover the possibility that this may shutdown several times a year.
However, it not occur, a maximum test interval of 6 months is specified.
is not our intent to require a plant to shutdown just to conduct the valve If licensees anticipate long duration power oper-leakage integrity tests.
ations with infrequent shutdown, then installation of a leak test connection
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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.
It is intended that the above proposed surveillance specification be applied to the active purge / vent lines, as well as passive purge lines:
1.e., the purge lines that are administratively controlled closed during reactor oper-ating modes 1-4.
The reason for including the passive purge lines is that B-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 no alve types and seating materials, the In view of the wide variety of acceptance criteria for such tests should be developed on a plant-specific basis.
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Enclosure ?
Use of Containment Purge / Vent Valves ',
1.
Purging / venting should be minimized during reactor operation because the plant is inherently safer with closed purge / vent valves (containment) than with open lines which require valv'e action to provide containment.
(Serious consideration is being given to ultimately requiring that future plants be designed such that purging / venting is not required during operation).
2.
Some purging / venting on current plants will be pennitted provided that:
al purging is needed and justified for safety purposes, and b) valves are judged by the staff to be both operable and reliable, and c) the estimated amount of radioactivity released during the time required to close the valve (s) following a LOCA either i.
does not cause the total dose to exceed the 10 CFR Part 100 Guidelines; then a goal should be established which represents a limit on the annual hours of purging expected through each particular valve, or ii. causes the total dose to exceed the guideline values; then purging / venting shall be limited to 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> / year.
3.
Purging / venting should not be permitted when valves are being used that are known to be not operable or reliable under transient or accident conditions.
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