ML20154D688
| ML20154D688 | |
| Person / Time | |
|---|---|
| Issue date: | 06/07/1988 |
| From: | Conran J Committee To Review Generic Requirements |
| To: | Committee To Review Generic Requirements |
| Shared Package | |
| ML20153B009 | List: |
| References | |
| NUDOCS 8809160058 | |
| Download: ML20154D688 (5) | |
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June 7, 1988 MEMORANDUM FOR:
CRGR Members FRON:
Jim Conran, CRGR Staff
SUBJECT:
Summary and Issues Identification for CRGR Agenda Items - Meeting No. 137, June 8, 1988 Enclosed are sumaries of, and issues identification for, the three items scheduled for consideration by the Committee at the subject meeting, as follows:
1.
Review of proposed Part 52 on Standardization 2.
Review of a proposed NRC Bulletin on Thermal Stratification and Temperature Cycling in Ping Connected to the RCS due to Valve Leakage 3.
Briefing on the proposed SER on the B&W Owner's Group Response to ATVS Rule Requirements If there are any questions, call me at 492-9855.
/s/
Jim Conran CRGR Staff ec:
S. Crockett, OGC M. Taylor, EDO NOTE: Authorized for transmittal by CRGR Chairman.
Transmitted at 2:15p, 6/7/88 9909160058 990617 PDR REVGP NRCCRCR NEETING137 PNV 4
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Summary and Issues Identification for CBGR Agenda Items - Meeting No.137 Jur.e 8,1988 1.
BULLETIN ON THERML STRESSES IN PIPING A.
Summary In response to an event at the Farley plant involving unanticipated, undetected thermal cycling, and ultimate failure, in ECCS piping due to leakage of an isolation valve, the staff is requesting all LWR licensees and permitees (1) to review piping systems connected to the RCS to determine whether unisolable piping sections could be subjected to stresses from temperature stratification and cycling that could result in similar failures, (2) to esamine non-destruct-ively the welds and heat-affected zones in piping that may have thus been subjected to excessive thermal stresses and cycling, and (3) to plan and implement a program to provide continuing assurance against such conditions / consequences.
The staff position appears to be that the requested actions are necessary to provide reasonable assurance of compliance with exist-ing regulations (e.g. GDC-14) at all LWRs, even though only one
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failure attributable to this mechanism has actually been observed, because the initiating cause (i.e., globe valve leakage) is ccanon among the operating plants.
The staff estimates that the cost of implementing the a:tions requested in the bulletin could be (1) 5100K plus 22-to-32 person rem per plant for the utilities, and (2) 240 person-hours total for the NRC staf f.
This expenditure of resources would restore the margin of safety that was intended by NRC in promulgating GOC-14; and the staff states that the total estimated slm cost to the utilities (and presumably the estimated total 2200-to $700 person rem occupational exposure as well) is i
reasonable fr' this increase in protection.
(The staf f does not i
state explienly that such increase is necessary for adequate protection.)
Issues / Questions 1.
The proposed bulletin apparently has not received OGC review and concurreece.
Even though the staff believes there are no issues that require it, shouldn't OGC review be obtained? As an example of the type of things OGC might consider, should 50.54(f) be cited as the basis for the information submittal requirement in Action 17 2.
On p.4 of Exlosure 2 of the review package, the staff states that a problee similar to the Farley problee has not been
identified for BWRs. Why then are BWRs included in the scope of the belletta? Clarify.
3.
On p.6 of Enclosure 2 of the review package, the staff states that the proocsed action is final (i.e., not an interim meas-ure). How dus the staff know that no further action will be required? How did the staff determine that the scope should be restricted as it is, in view of the fact that valve leakage is regarded as common? Aren't there similar plant conditions and pipe-and valve configurations elsewhere in the plant (e.g., in the balance-of plant systems) where similar circumstances could occur? Have the possible effects of a high common mode failure rate in balance-of plant piping due to this pervasive mechanism (e.g., unacceptably high transient and accident initiation rates and/or resultant plant conditions that defeat or overwhele the safety systems) been adequately considered?
4.
Although the compliance concern and argument may seem (axiomat-ically) a valid one, is it really necessary to place such rigid reliance en compliance with GDC-14 in this case, in view of what is now known regarding leak-before-break (new information obtained since GDC-14 was developed and promulgated)? Does the staff beltete, from having thought it through carefully in this instance, that rigid compliance with GDC-14 is necessary for adequate protection / safety, where the chance of undetected stress cracking and rapidly propagating failure is by their own assessnest low - (e.g., see p.6 of Enclosure 2)? Does the staff have any feel for the magnitude of the core melt improve-ment increment that will be realized by implementing the proposed bulletin? Or what core melt improvenent increment would be needed (at 51000/mres) to balar.:e the estimated $10M cost involved?
II. B&W OWER'S GROUP GD4ERIC rep 0RT ON THE ATVS RULE in a nutshell, the issue in this item is whether the proposed SER requires CRGt review. The staff believes that it does not, because this SER applies to B&W plants positions that were pt stously applied to Westinghouse and CE plants.
The staf f mainuins that those positions derived directly free laterpretations of ATVS Rule wording included in the Statement of Considerations accompanying that rule.
In their view, then, the interpretations / positions they are using have been reviewed and approved not just by Ntt management, but by the Commission itself. They are, therefore, not "new' positions that require review by CRGR. Accord-ingly, the Westinghouse and CE SERs were not brought before CRGR prior to being issued.
The difficulty at this point is that, while Westinghouse and CE apparent-ly accepted the staff's views regarding proper interpretation of the rule's language and requirements, the B&W CNners' Group have not. The principal disagreeerst is over the meaning of the word "independent" as it applies to the power supply for the actuation device circuitry in the
diverse scraa systes (D55) required by the rule (50.62 c.2.).
The staff position has been that the electrical power source must be from a source (e.g., a battery) cther than an existing, currently installed Class IE RPS power supply. The RdOG disagrees; and, although the detatis of their disagreement with the staff are not known fully at this time (because the staf f has not yet provided a copy of the BWOG position for evaluation),
it appears free a preliminery review of the B&W SER and discussions with the staff, that the wording of the SER does go somewhat beyond the language of the Rule and the Statement of Considerations taken together.
The CRGR staff view is that (1) because the statement of the staff's position goes beyoed the wording that has been approved by the Commission in the rulemaking package, (2) because the BWOG challenge reasonably raises questions regarding the staff's reading of the language involved, and (3) because the staff s position has not been "previously approved" through a process that includes review by CRGR (as specified in the Charter), the matter warrants review by the Committee at thir. time. The staff has repested the opportunity to brief the CRGR on this matter, before investing tre ccasiderable amount of ef fort required to prepare a complete review pa:kage, in the belief that the Committee will agree that a full, formal review is unnecessary.
(The staff has agreed to provide directly to Committee seebers copies of the BWOG challenge to the staff's position before Meeting No.137 to suppert informed discussion of these questions at the briefing.)
III. PROPOSED RULE ON STANOMOIZATION (10 CFR50 PART 52)
Expedited review by CM4 has been requested on this proposed rule to support a mid-Sumer issue for comment goal established by the NRC Chairman. This pr:;csed rule is related to the two Commission Papers on Advanced Reactors revieed recently by the Ccerittee, but is broader in scope. The staff cecnttted to provide to the Committee a revised version of the rule reflecting CRGR comments on those two items and the staff's disposition of those cements.
Due to the late receipt of a set of Congressional westions that that bear directly on this matter and which OGC m&y want to reflect in the revised package, the revised version of the proposed Part 52 rule was not availablo at COB Monday, 6/6/88; but the staff intuds to provide directly to Committee members before Meeting No.137 that revised package.
On the basis of conversations between CRGR staf f and the sponsoring of fice staff, the Coenittee can expect and may wish to focus on the following changes to the version of the Part 52 package distributed under separate cover earlier that will be contained in the revised version:
1.
The revised draft Part 52 will conform to changes made by RES in the two Advaxed teactor Comission Papers as a result of CRGR coments.
(Copies of the reconvnendations f rom CRGR Meetings Nos.135 and 136 will be available at Meeting No.137 for review and comparison purposes.)
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2.
The revised draft Part 52 will likely contain a revised treatment of l
backfitting considerations, reflecting staff discussion with ACRS l
and their comments regarding the a;propriateness of the so-called l
"finality" provisions and requirements for certification of existing design approvals.
3.
A revised treatment of early site "redress" (ala Clinch River), and consideration of industrial use bef ore redress, will probably be included in the revised package.
4.
Some form of treatment of the "replication" option may be added to the revised package. This may take the form of a proposed policy, rather than explicit treatment in the proposed rul, because of unresolved differences within the staff on this question.
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