ML20056E524
| ML20056E524 | |
| Person / Time | |
|---|---|
| Issue date: | 07/07/1993 |
| From: | Rogers K NRC COMMISSION (OCM) |
| To: | Chilk S NRC OFFICE OF THE SECRETARY (SECY) |
| References | |
| NUDOCS 9308240181 | |
| Download: ML20056E524 (5) | |
Text
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EM S CEOTOTHEPDR NOTATION VOTEi, _f/_gLg 3 g,
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RESPONSE SHEET 2 * + "O* " " " " U II* " d T0:
SAMUEL J. CHILK, SECRETARY OF Tile C0f4HSSION FROM:
C0!41ISSIONER R0GERS
SUBJECT:
SECY-93-087 - POLICY, TECHNICAL, AND LICENSING ISSUES PERTAINING TO EVOLUTIONARY AND ADVANCED LIGHT-WATER REACTOR (ALWR)
DESIGNS A P P R O V E D ' io farer
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- ABSTAIN NOT PARTICIPATING REQUEST DISCUSSION COMMENTS:
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RELEASE VOTE
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(ITATE WITHHOLD VOTE
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COMMISSIONER ROGERS' VOTE / COMMENTS ON SECY-93-087 l
Approved in cart; Disapproved in part
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I join Commissioners Remick and de Planque in.their commendation of the staff for the thorough _ analysis of the policy issues l
addressed in SECY-93-087.
My approval and disapproval by issue is provided below with accompanying comments where applicable.
I 1.
I.E.
Fire Protection i
I approve the staff position.
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f 2.
I.F.
Intersystem Loss-Of-Coolant Accident I approve the staff position.
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3.
I.G.
Hydrocen Control j
l I approve the staff position as presented in the SECY paper.
l With regard to the staff's proposed consideration of j
autocatalytic recombiners as discussed in the Commission meeting, I caution the staff to consider carefully the relatively slow time response of autocatalytic recombiners as a possible impediment to the efficacy of such l
recombiners.
J F
4.
I.H.
Core Debris Coolability f
I approve the staff position, and support Commissioner i'
Remick's comments that'the staff should permit licensees to utilize other technically justified methods for demonstrating adequate containment response to debris coolability.
5.
I.T.
Hich Pressure Core Melt Eiection I
I I approve the staff position.
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6.
I.J.
Containment Performance a
I approve the staff position.
i 7.
I.K.
Dedicated Containment Vent Capability j
I approve the staff position.
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1 8.
I.L.
Eauipment Survivability l
t I approve the staff position.
I 9.
I.M.
Elimination of Operatino-Basis Earthauake (OBE) 1
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j I approve the staff position.
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10.
I.N.
Inservice Testina of Pumps and Valves I have no objection to the staff position herein, but understand that further elaboration on this issue will be forthcoming from the staff and will respond to that after I have reviewed it.
11.
II.A. Industry Codes and Standards I approve the staff position.
12.
Il2D. Leak Before Break I approve the staff position.
13.
II.E. Classification of Main Steamlines in Boilina Water _
Reactors I approve the staff position.
14.
II.F. Tornado Desian Basis I approve the staff position.
15.
II.H. Containment Leak Rate Testina I approve the staff position.
16.
II.I. Post-Accident Samplina Syst_gn I approve the staff position except, that I join Commissioners Remick and de Planque in limiting post-accident sampling systems for evolutionary and passive Pressurized Water Reactors to possess the capability to determine the cross amount of dissolved cases (not necessarily a pressurized sample) and to exclude the requirement for determining chlorides in the primary coolant as an accident mitigation consideration.
17.
II.N. Site-Soecific Probabilistic Risk Assessments and ADg3vsis of External Events I approve the staff position, except that I join Commissioners Remick and de Planque in disapproving the staff's recommendation to use two times the Desian Basig Safe Shutdown Earthauake (SSE) for probabilistically-based seismic margins analyses of seismic events which would consider sequence-level HCLPFs and fragilities for all sequences leading to core damage of containment failure up to approximately one and two-thirds the around motion acceleration of the Design Basis SSE.
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3 The reason for this change in the staff's recommended position is two-fold as outlined in Commissioner Remick's votc sheet.
T am informed that for meat sites selected in the U.S.
for advanced designs, the site-specific SSE will be less than 0.3g and the ratio of ground motion acceleration of the Seismic Margin Earthquake (SME) of 0.5g used in the analysis will be greater than one and two-thirds that of the site specific SSE (and possibly larger).
- Moreover, continued specification of 0.5g as the SME would enable vendors to continue existing safety margins and bases for equipment qualification which have been previously developed and which the staff has deemed adequate.
I also note that the Nuclear Safety Research Review Committee (NSRRC) in its letter of January 14, 1993 expressed serious reservations with new proposed seismic regulation:
(n"* Appendix B of 10CFR100) which involve,a dual appicach o ' probabilistic analysis and traditional deterministic ciimparisions, but with deletion of the "capabie" fault and its replacement by " capable tectonic sourcc th At ir not well defined.
The NSRRC concern, as well as mina: is that the propor.ed dual approach makes the new regulation less well defined than the old regulation and i
provides no guidance for for assessing seismic risks.
The appropriate NRR office should consider the NSRRC concerns on this matter.
18.
II.O. Defense Acainst Common-Mode Failures in Dicital Instrumentation and Control Systems i
I approve the staff position, except that I join Commissioner Remick's position (as modified by Commissioner de Planque) that postulated common-mode failures for the vulnerability assessment which are performed by the vendor or applicant would include each event evaluated in the accident analysis section usina best-estimate methods, for which adequate diversity would have to be demonstrated.
Moreover, the controls and displays located in the main control room for manual, system-level actuation of critical safety functions and monitoring of parameters supporting i
safety functions, need not themselves be safety arade since the system itself 1.ould be of safety-grade quality.
Finally, I agree with Commissioner Remick that the i
requirements of paragraph 4 on page 57 appear overly prescriptive and detailed, therefore, I approve only the underlined sentences in Section 4.
I also would prefer that such prescriptiveness be considered as guidance and determined on a case-by-case basis.
19.
II.R.1.
Multigle Steam Generator Tube Ruotures t
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4 I approve the staff position.
II.R.2.
Containment Bvoass Potential Resultina from SGTRs.
I approve the staff position.
20.
II.
T.
Control Room Annunciator (Alarmi Reliability L
I approve the staff ~ position.
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21.
III.H.
Role of the Passive Plant Control Room Operator I approve the staff position.
22.
Finally, during the Commission meeting with EPRI representatives on June 10, 1993, these representatives stated
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that the final staff position on several issues in SECY-93-087 had not been discussed fully with EPRI.
I join Commissioners Remick and de Planque in their proposal that the staff and industry meet to ensure common understanding of the above l
requirements.
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