ML20246F508
| ML20246F508 | |
| Person / Time | |
|---|---|
| Issue date: | 12/13/1988 |
| From: | Conran J Committee To Review Generic Requirements |
| To: | Bernero R, Goldberg J, Jordan E Committee To Review Generic Requirements, NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS), NRC OFFICE OF THE GENERAL COUNSEL (OGC) |
| Shared Package | |
| ML20245E100 | List: |
| References | |
| NUDOCS 8907130284 | |
| Download: ML20246F508 (5) | |
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. ) UNITED STATES RELEASED TO THE PDR NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555
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December 13, 1988 MEMORANDUM FOR: Edward L. Jordan, Chairman Robert M. Bernero, HMSS Jack R. Goldberg, 0GC Carl J. Paperiello, RIII Denwood F. Ross, RES James H. Sniezek, NRR THRU: C.J. Heltemes, Jr. , Deputy Director Office for Analysis and Evaluation of Operational Data FROM: James H. Conran SeniorProgramManager(CRGRSTAFF)
Office for Analysis and Evaluation of Operational Data
SUBJECT:
ISSUE IDENTIFICATION SHEET FOR MEETING NO. 152 AGENDA ITEM Enclosed for your information is an Issue Sheet, and additional background documents, relating to CRGR review of the propcsed Mark I improvements package scheduled for review by the Committee at Meeting No. 152 in Rocm 6507, MNBB, 1:30 - 3:30 p.m. on Wednesday, December 14, 1988. If there are any questions, call me at 492-9855.
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'Janies H. Conran Senior Program Manager (CRGR Staff)
Office for Analysis and Evaluation of Operational Data i
Enclosures:
As stated i
cc: C. Sakcnas V. Stello M. Taylor /
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9907130284 881213 (. .;r f
PDR REVGP NRCCRGR MEETING 102 PDC
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Sumary, and Issue Identifica,ti,on fnr CRGR Agenda Item - Meeting No.152
' December W ,'l)B8 l
IDENTIFICATION Proposed Comission Action Paper, " Mark I Containment Performance Improvement Program." This paper presents staff recommendations on measures (including i
both plant modifications and emergency procedures upgrading) to improve Mark I l containment severe accident performance capability.
OBJECTIVE The purpose of the proposed Comission Paper is to obtain Comission approval for the staff to proceed with the_ implementation of_ a recomended program of Mark I containment modifications, and related safety enhancements (e.g.,
I procedure improvements) aimed at improving significantly severe accident
- performance. capability of the Mark I containments. The recomended course of action includes issuing a Generic Letter (to begin expeditiously the intended
-upgrading), followed by a rulemaking (to codify as legal requirements the recommendedupgrades).
i BACKGROUND The documents'provided to the CRGR for review in this matter were transmitted officially by two memoranda, (1) dated December 7,1988, E.S. Beckjord and T.E. Murley' to E.L. Jordan 1, and (2) dated December 9,1988, E.S. Beckjord to .
E.L. Jordan (seeattached)). The documents transmitted by these memoranda for review by CRGR were as follows:-
- 1. Draft Commission Paper (undated), " Mark I Containment Performance Improvement Program", and attachments as follows:
- a. Enclosure 1 - Responses to August 1, 1988 SRM
- b. Enclosure 2 - Table, " Mark I Challenges and Relative Likelihood of Failure Modes"
- c. Enclosure 3 - Sumary of Costs
- d. Enclosure 4 - Regulatory Analysis
- e. Enclosure 5 - EWR Mark I Plant Survey
- 6. Enclosure 6 - BWR/ Mark i Liner Failure Issue
- 7. Enclosure 7 - Oraf t Generic Letter, "Prcposed Severe Accident Requirements for Plants with Mark I Containments"
- 8. Appendix A . Backfit Analysis (seeattached)
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- 2. Sumary Infonnation for CRGR - Proposed Mark I Containment Enhancements (in accordance with Section IV.B. of the CRGR Charter)
- 3. Memorandum, dated December 9,1988, F.P. Gillespie to R.W. Houston, transmitting NRR coments on proposed Mark I enhancements package.
(seeattached)
DISCUSSION / ISSUES
- 1. The Committee was provided a briefing on an earlier, similar package of proposed Mark I upgrade measures at Meeting No.104; CRGR coments/
suggestions that resulted from that meeting are enclosed. The Committee may wish to pursue further with the staff some of those earlier coments, and the manner in which they are addressed in the current review package; for example:
- a. Both the Commission and the CRGR questioned earlier whether a rule-making (rather than a generic letter) might not be a more appropri-ate way to approach upgrading Mark I containments to improve their severe accident (i.e., beyond design basis) performance capability.
The staff's response is to now recommend imposition of significant severe accident upgrades by generic letter, followed by a rulemak-ing to codify the new requirements. This answer seems to beg (if notoutrightflaunt)thequestionasked. In further view of the lack of OGC concurrence on the package transmitted for review, this important procedural question would appear to warrant pursuit by the Committee.
- b. The Committee commented earlier that notification of the public prior to venting should be addressed. I could find no direct respense to this Committee coment'in the current package. In the discussion of implementation of Rev 4 of the BWR EPGs the current package (seeEnclosure1totheCommissionPaper, Topic 4),the staff notes that the EPGs address technical issues relating to venting, but do not er:dresss emergency planning or political i considerations presumably, such as notification of the public beforeventing)(. Beyond that statement, however, I could find nothing else that even indirectly addressed the Committee's earlier comment. The Committee may wish to consider whether the staff has adequately addressed this important question in the current package.
(Harking back to 1.a. above in this context, it is perhaps worth noting that, in a (Mark I) rulemaking that preceded issuance of a generic letter, the question of notification of the public prior to venting could get a thorough airing, along with the closely-related question of whether it is necessary to prepare an environmental statementontheeffectsofventing.)
- c. The Committee commented earlier that implementatico of the Station Blackout (SBO) Rule may obviate the need for (Marx I) containment modifications. The current package addresses the SB0 Rule and the ATWS Rule, together with the proposed Mark I enhancements, t.nd the staff estimates that the core melt frequency improvement expected to be achieved by implementing all three is about one order of magnitude.
But the staff never clearly indicates / quantifies, in the current package, what is the expected incremental CMF improvement attrib-L _ - - _ - - - - _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
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utable to Mark I improvements alone. The ATWS and SB0 rule require-ments that have already been approved would appear to contribute a very substantial fraction of the total berefits claimed for the combination of all three taken together. By arguing that there is small benefit to accelerating the implementation of these rules, it is made less clear thatl implementation of those rules on the
- existing schedule provides a very substantial benefit; and it is {
l almost made to appear that those already-approved rule requirements j must be taken together with the proposed Mark I improvements to be adequately justified. The staff should clarify their intent'in this ]
regard, and attempt to sort out more clearly the benefits /justifi-cation of just the additional backfits being proposed in this package.
As a closely related issue, the Committee should give attention to the staff's treatment of Alternatives in the Regulatory Analysis that accompanies this package. (See Reg. Analysis at pp.14-18). I The staff argues that sufficient justification does not exist for chocsing any of the Alternatives, (ii) - (v), considered separate-ly,, but then recommend in favor of an asserted synergistic combin-ation of all those Alternatives taken together. (A sort of "all, or nothing at all" approach to backfitting.) It should first be noted that, while the staff's analyses do show that Alternatives (ii), f (iv), and (v) are not separately justified backfits, Alternative {
(iii) would appear to qualify separately as such, on its face. The staff seems to have rejected it as a separately justified backfit by resort to an assumed (but as yet unapproved) severe accident
" defense-in-depth" requirement. As a second comment, the syn-ergistic effect, whTch the staff expects to realize by combining separately unjustifiable Alternatives, seems more asserted than demonstrated in this package. As a final coment regarding the subject Regulatory Analysis, one is led in view of all the preceding, to seriously wonder about the factor-of-three-or-so discrepancy between the staff's estimate of cost and the actual cost experience of one licensee in implementing Mark I upgrades such as those proposed in this package.
t The Committee should ask ihe staff for further clarification on all of '
the above points. Afterwards, the Comittee may wish to consider recommending (again?) to the EDO that the staff be charged to provide, aa part of each package brought to the CRGR for consideration, some kind of credible cumulative accounting / perspective of the CMF/ risk
- l benefit that has been a'chWved through the staff's continuing generic {
issue resolution efforts.
- 2. Notwithstanding the clear impression given by the joint RES/NRR transmit-tal letter sent to CRGR with this package, it does not appear that NRR ,
has actually concurred in the groposed backfits (only in the package l
" going forward for CRGR review - seeBackgroundItem3., attached).
Also, although OGC review has been requested, CRGR has not been provided their coments on this package (as of COB 12/12/88). HRR's coments (see attacted) need to be resolved; and OGC's perspective or the kinds of {
questions posed in 1.b. above (i.e., rulemaking vs generic letter, anc I thepossibleneedforanenvironmentalstatementoncontainment),and probably others, needs to be obtained. These matters can be discussed further at the upcoming meeting, cf course, and should be. But it seems
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worth noting, as indicated in the attached excerpts frem the Meeting 104 I minutes, that in earlier (not necessarily less hectic) times, with the l same concurrences lacking, the package was simply nct submitted (or I accepted)forCRGRreview.
- 3. With reference again to the relationship between the Station Blackout Rule and this proposal for Mark I improvements, if a licensee chose to upgrade electric power systems sufficiently to achieve the so-calld "zero hour" level of (blackout coping) capability for his plant, would that licensee still be required to do significant upgrading under the provis-ions of this package, if approved? Have these kinds of possible dis-incentives (to significant electric power system improvements) been adequately considered in connection with this proposal, or has too great an emphasis been placed on achieving " balance" between prevention and mitigation?
- 4. The Committee may wish to discuss further with the staff the crigin, ;
rationale and implications of several differences apparent between the measures proposed in the earlier version of this package considered at Meeting No.104, and those in the current package:
- a. The previous preposal called for at leat,t two backup water supply systems for containment drywell spray, and adjustment of the spray nozzles so that an evenly distributed spray pattern would be developed whether water was supplied from primary or backup supply.
The current proposal calls for at least one backup water supply for supplying water to either the drywell sprays or to the reactor vessel for core cooling, with no requirement for spray nozzle adjustment.
- b. Proposed enhancements to the Automatic Depressurization System (ADS) have been added in the current package, including severe accident EQ requirements for ADS cabling.
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Explicit instrumentation backup water requirements supply to drywell sprays and(for accomplishing) reactor delivery of vessel have been l added in the current proposal.