ML14077A019

Final Cooper Section 3 4 IE PRA Record-of-Review 03-13-2014

ML14077A019
Person / Time
Site:	Cooper
Issue date:	03/28/2014
From:	Office of Nuclear Reactor Regulation
To:
O'Neal D, NRR/DRA, 415-5539
References
Download: ML14077A019 (2)

Text

Record of Review Dispositions to Cooper Nuclear Station Internal Events PRA Facts and Observations (F&Os)

F&O DISPOSITION ACCEPTABLE TO STAFF VIA Review of SUPPORTING Plant RAI Response REQUIREMENT Disposition (SR) (A/B/C) Not Discussed in SE Discussed in SE AS-A2 See PRA RAI-01d and F&O disposition.

The licensee confirms that examination of thermal-hydraulic analyses demonstrates that event sequences modeled in the PRA, including the sequence cited by the peer review, reach a stable state. Given the additional information, the NRC staff finds the disposition to the F&O to be acceptable.

DA-E1 C DA-E3 A HR-G6 B HR-G7 See PRA RAI-01a and F&O disposition.

Acceptable to the NRC staff because the licensee stated that two minimum values for joint HEPs were utilized and based on timing considerations, and that for the specific combinations referenced by the peer review, the HFEs in each combination were independent.

HR-I3 See PRA RAI-01b and F&O disposition.

Acceptable based on NRC staff confirmation that the licensee followed an acceptable approach of identifying and documenting sources of model uncertainty and related assumptions associated with the CNS Internal Events PRA, includes using guidance from NUREG 1855, Guidance on the Treatment of Uncertainties associated with PRAs in Risk Informed Decision Making, and EPRI TR-1016737, Treatment of Parameter and Model Uncertainty for Probabilistic Risk Assessment. The NRC staff also confirmed during the audit that the key assumptions and uncertainties are discussed in detail in the PRA Summary Notebook.

IE-A7 B IE-D3 See NRC staff review for SR HR-I3 regarding licensee response to PRA RAI-01b.

IF-B1 C IF-B2 C IF-F3 C LE-G5 A MU-B2 See PRA RAI 20 in SE Section 3.4.2.2.

MU-E1 A MU-F1 A QU-D4 See PRA RAI-01f and F&O disposition.

Acceptable to the NRC staff because the licensee stated that reasonableness reviews were performed by examining the cutsets of those fire scenarios that individually contribute greater than 1% to CDF and LERF, which includes non-significant cutsets. In addition, numerous low contributors were evaluated to ensure that they correctly represented risk contribution.

QU-E3 See PRA RAI-01c and F&O disposition.

Acceptable to the NRC staff because the licensee confirmed in the RAI response that state of knowledge correlations (SOKCs) were performed for plant specific data as well as for non-plant specific data.

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Record of Review Dispositions to Cooper Nuclear Station Internal Events PRA Facts and Observations (F&Os)

F&O DISPOSITION ACCEPTABLE TO STAFF VIA Review of SUPPORTING Plant RAI Response REQUIREMENT Disposition (SR) (A/B/C) Not Discussed in SE Discussed in SE QU-F5 See PRA RAI-01g and F&O disposition.

Acceptable to the NRC staff because the licensee identifies a list of acceptable techniques that were used to help minimize limitations in the quantification process.

SC-B3 B SC-C3 See NRC staff review for SR HR-I3 regarding licensee response to PRA RAI-01b.

SY-A14 See PRA. RAI-02.l and F&O Disposition Acceptable to the NRC staff because, although the cited failure modes were originally considered low probability and excluded, the response to the RAI explains that, in fact, these failure modes are evaluated and documented for the Fire PRA. The response details all the different forms of the cited failure modes that were considered.

SY-A4 See PRA RAI-01e and F&O Disposition.

Acceptable to the NRC staff because walkdowns and interviews were specifically performed to confirm the as-built configuration of the plant. At the audit, the NRC staff confirmed that the licensees PRA configuration control procedure also requires validating the PRA model with plant personnel. In response to NRC staff PRA RAI-01e, the licensee adequately describes the system walkdowns and interviews performed to confirm that the PRA system analysis reflects the as-built, as-operated plant.

A: The NRC staff finds that the disposition of the F&O as described by the licensee in the LAR provides confidence that the issues raised by the F&O have been addressed and, if needed, the PRA has been modified, and therefore the resolution of the F&O is acceptable for this application.

B: The NRC staff finds that the disposition of the F&O as described by the licensee in the LAR and further clarified during the audit provides confidence that the issues raised by the F&O have been addressed and, if needed, the PRA has been modified, and therefore the resolution of the F&O is acceptable for this application.

C: The NRC staff finds that the resolution of the F&O, as described by the licensee in the LAR, would have a negligible effect on the evaluations relied upon to support fire risk evaluations and has no impact on the conclusions of the risk assessment and therefore the resolution of the F&O is acceptable for this application. Examples of such F&Os may be suggestions, as well as those F&Os that don't affect the fire PRA. Documentation issues may fall into this category as well.

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