NSD-NRC-96-4867, Forwards Revised Info Re Status of Regulatory Treatment of Nonsafety Systems.Westinghouse Submitted WCAP-13856, Providing Results of Application of Probabilistic & Deterministic Evaluation to AP600
| ML20132D119 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 12/09/1996 |
| From: | Mcintyre B WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NSD-NRC-96-4867, NUDOCS 9612190216 | |
| Download: ML20132D119 (6) | |
Text
ex 1
/
\\
/
n t
)
\\v; Westinghouse Energy Systems g5sp_
gg,5, Electric Corporation NSD-NRC-96-4867 Rev.1 DCP/NRC0644 Rev.1 Docket No.: STN-52-003 December 9,1996 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555 ATTENTION:
T.R. QUAY
SUBJECT:
REGULATORY TREATMENT OF NONSAFETY SYSTEMS (RTNSS)
STATUS References 1:
NRC letter to Westinghouse, Crutchfield to Liparuto, " List of Key Licensing Issues on the AP600 Design," dated 3/21/95.
2:
Westinghouse letter to NRC, McIntyre to Quay, "AP600 Passive System Reliability Roadmap," dated 8/9/96.
Dear Mr. Quay:
Revision 1 of this letter is issued to reflect completion of the focused PRA evaluation for subissue 2 and finalizing the date for the ASI telecon for subissue 3, and to include the Table referred to under subissue 6.
The simplified nature of the AP600 design results in a number of systems that are classified as safety-related in current plants being classified as nonsafety-related. While the licensing basis for the AP600 relies solely on these safety-related systems, the NRC has raised the issue of what, if any, additional regulatory oversight should be applied to these systems. The initial discussions on the regulatory treatment of nonsafety systems (RTNSS) were held between the NRC staff and the ALWR Utility Steering Committee in January,1993. In May,1993, agreement was reached between the NRC staff and the industry on the RTNSS resolution process, which included both probabilistic and deterministic evaluation criteria. In September,1993, Westinghouse submitted a report, "AP600 Implementation of the Regulatory treatment of Nonsafety-Related Systems",WCAP-13856, that provided the results of
}
the application of these criteria to the AP600. This submittal included proposed additional regulatory
}
oversight to provide the staff with the high level of confidence that active systems would be available i
{g(
when challenged. As described in the agreed to approach, this proposed regulatory oversight was consistent with the identified systems reliability / availability mission.
The agreed to RTNSS resolution process was reviewed by the Commission in SECY-94-084, " Policy and Technical Issues Associated with the Regulatory Treatment of Nonsafety Systems in Passive Plant Designs", March 28,1994. The SRM on SECY-94-084 was issued on June 30,1994.
9612190216 961209 PDR ADOCK 05200003 A
NSD-NRC-96-4867 December 2,1996 DCP/NRC0644 During a March 29,1995 RTNSS meeting, the application of the RTNSS process to the normal RHR system was reviewed with the staff as a specific example of the implementation process.
During the February 9,1995 Westinghouse /NRC AP600 Senior Management Meeting (SMM), several key subissues were identified and discussed which constitute the elements that require closure to complete implementation of the RTNSS process.
i The attachment to this letter documents the status for each of the identified RTNSS subissues.
Implementation of the RTNSS resolution process is a key item with respect to completion of the AP600 FSER. It is therefore essential that this program be revitalized and given the attent. ion it I
requires.
)
I will contact you prior to the Westinghouse /NRC senior management meeting on December 9 to discuss how to go forth on this' issue so as to reach resolution in a time frame that supports our schedule.
w Brian A. McIntyre, Manager Advanced Plant Safety and Licensing
/nja Attachment cc:
T. Martin, NRC/NRR W. Huffman, NRC/NRR N. Liparulo, Westinghouse (w/o attachment) wm
ATTACIBiENT TO DCP/hRC0644 i
i STATUS OF RTNSS KEY SUBISSUES 1.
Thennal-hydmulic Uncertainty I
We believe consensus was reached on a resolution path for acceptability of the baseline PRA, l
-including passive system reliability and T&H uncenainty issues and that there is enough conservatism in the baseline PRA to offset the T&H uncenainty issues. Westinghouse
)
submitted a passive system reliability roadmap by Reference 2 in response to an NRC request.
Westinghouse has the action to beruiniurk MAAP4 against NOTRUMP and to complete the T&H Uncenainty Evaluation. There activities are included on the AP600 Design Certification Activity Schedule provided to the hRC.
2.
NRC acceptance of the AP600 PRA The final Focused PRA was submitted on September 30,1996. The initiating event frequency evaluation was submitted on October 14,1996 and the focused PRA RTNSS evaluation is l
d 6'd f-t = d".: was sent on November 1,1996. No additional RTNSS-important systems have been identified. It is an NRC action to document acceptability of the Focused PRA.
1 J
3.
Adverse Systems Interactions On October 3,1996, the NRC provided review comments on WCAP 14477 the Adverse Systems Interactions, submitted in March of 1996. Westinghouse is addressing those l
comments in preparation for a resolution meeting with the NRC, rddy scheduled for the l
' " December M 20,1996.
4.
Post-72 hour Actions j
Post-72 hour actions is one of the policy issues before the Commission in SECY-96-128 and J
regtures Commission action to go forth. This action is anticipated in the very near future.
Westinghouse has reviewed the proposed policy statement before the Commission and is prepared to rapidly move forth with whatever actions are rey to address this issue orre the Commission makes a decision on the SECY paper.
l {-
l m-.
~ -..
- - - - ~.~.-__._~
c i
i l
Attachment to DCP/NRC0644 5.
i l
. The safe stable condition for the AP600 is dermed as hot standby since the passive RHR system is highly reliable and no single active failure can prevent its termmation. However, the staff was concemed that a small earthquake can make the standby ac power supply unavailable j
and has not determmed acceptability of this design.
j i
i l
As discussed during the January 1995 RINSS meeting, the Westinghouse position is that j
i seismic design and qualification is beyond the criteria agreed to in development of the RTNSS process 'Ihermal cycling issues resulting from passive system actuation during small seismic
. events (less than SSE) were also addressed. This issue is closed, with NRC agreement that no seismic criteria will be applied uniformly to RINSS-important equipment but can be applied if i
that equipment performs a mission with seismic implications.
I i
6.
Additional oversight once RTNSS functions are identified beyond what is already prosided,'
(SSAR review, D-RAP, ITAAC, maintenance mle, etc.).
j WCAP-13856, provided proposed additional regulatory oversight for the systems identified as
~
R1NSS inportant to provide the staff with the high level of confidence that active systems would be available when challenged. As described in the agreed on approach, this proposed regulatory oversight was consistent with the identified systems reliability / availability mission.
To assist the NRC with completion of their RINSS-related activities for the AP600 FSER,.
Westinghouse has created the attached AP600 Regulatory Oversight table which shows what additional regulatory oversight is spropiate for RTNSS-important systems identified. Also included in this table to provide a proper rupcetive on regulatory oversight are the regulatory oversights applied to safety related, as well as RTNSS, DID, and other non-safety related systems and functions. If new RTNSS important systems are identified, the appropriate regulatory oversight will be established.
i l
2-um
b Attachment to DCP/NRC0644 AP600 REGULATORY OVERSIGHT Regulatory Safety Non-Safety Non-Safety Ovenight Related RTNSS Related - DID Related-Other Reporting:
50.72/3 (Red Phone)
X License X
Tech Spec's X
10CFR21 X
License Events Reports X
X X
X License Commitments X
X X
X Maintenance Rule X
X X
X INPO Reports (SOER, SER, Etc.)
X X
X X
NRC Resident Reports X
X X
X Documentation /
Commitments:
SSAR Description X
X X
X Administration Procedures X
X X
X Appendix B QA Program X
QA Program - Graded X
X X
10CFR 52 Tier 1 X
X X
ITAAC X
X X
SSAR Chapter 14 Testing X
X X
X PRA X
X X
X Design Features /
Requirements:
Seismic 1 X
Class IE Power X
Industry Codes &
Standards (Reg. Guides, NUREGs, IEEE, ASME, Etc.)
X X
X X
Inspections:
Tours X
X X
X NRC Inspection Teams X
X X
X mi' 1
)
i.
Attachment to DCP/NRC0644 l
i AP600 REGULATORY OVERSIGHT Regulatory Safety Non-Safety Non-Safety Ovenight Related RTNSS Related - DID Related-Other SALP ratings X
X X
X Availability Controls:
Technical Specifications X
RTNSS Identified Administrative Controls X
Maintenance Rule X
X X
X i
I mm