ML19226A292

Draft Request for Additional Information for Palisades License Amendment Request to Adopt TSTF-425

ML19226A292
Person / Time
Site:	Palisades
Issue date:	08/05/2019
From:	Kimberly Green Plant Licensing Branch III
To:	Miksa J Entergy Nuclear Operations
References
L-2019-LLA-0070
Download: ML19226A292 (6)

Text

. . .[a] discussion of the resolution of the peer review . . . findings and observations that are applicable to the parts of the PRA required for the application [including] a discussion of how the PRA model has been changed [or] a justification . . . that demonstrates the accident sequences or contributors significant to the application decision were not adversely impacted . . . by the particular issue. Plants implementing TSTF-425 shall evaluate their PRAs in accordance with this regulatory guide [RG 1.200, Revision 2]. The RG specifically addresses the need to evaluate important assumptions that relate to key modeling uncertainties (such as reactor coolant pump seal models, common cause failure methods, success path determinations, human reliability assumptions, etc.). Further, the RG addresses the need to evaluate parameter uncertainties and demonstrate that calculated risk metrics (e.g., CDF [core damage frequency] and LERF [large early release frequency]) represent mean values. The identified "Gaps" to Capability Category II requirements from the endorsed PRA standards in the RG and the identified key sources of uncertainty serve as inputs to identifying appropriate sensitivity cases.

PNP is installing a number of plant modifications for NFPA 805 implementation that impact the PRA model. The PNP model infrastructure allows for enabling or disabling of these modifications as needed to ensure the model reflects the current plant, as-built and as-operated. When performing STI evaluations, the PNP model will only credit NFPA [National Fire Protection Association] 805 modifications that are currently installed and reflected in current plant procedures.