ML102580398

Requests for Additional Information (Srxb) EPU License Amendment Request

ML102580398
Person / Time
Site:	Point Beach
Issue date:	09/08/2010
From:	Beltz T Plant Licensing Branch III
To:	Hale S Point Beach
beltz T, NRR/DORL/LPL3-1, 301-415-3049
Shared Package
ML102580411	List: ML102580394 ML102580398
References
TAC ME1044, TAC ME1045
Download: ML102580398 (2)

Text

REQUESTS FOR ADDITIONAL INFORMATION Point Beach Nuclear Plant, Units 1 and 2 Extended Power Uprate (EPU) License Amendment Request (LAR-261)

Reactor Systems Branch (SRXB) Review (TAC Nos. ME1044 and ME1045)

SRXB-1 Please demonstrate that the margin-to-overfill consequences of a postulated steam generator tube rupture (SGTR) are no greater at EPU power level than at the currently licensed thermal power level.

SRXB-2 The margin-to-overfill SGTR analysis does not appropriately characterize limiting plant initial conditions or uncertainties. In light of the narrow margin to overfill without acceptably characterized uncertainty, please provide the information referenced in Requirement (3) of the NRC staff SER approving WCAP-10698 regarding the main steam lines and associated supports under water-filled conditions.

SRXB-3 Two better-estimate thermal-hydraulic analyses were described; one evaluated margin to overfill with a minimum RCS temperature and 10-percent tube plugging, while the other supplemented the dose analysis with a maximum RCS temperature and 0-percent tube plugging.

Please provide a summary statement comparing the purposes of these two analyses, and explain how the different initial condition assumptions achieved each intended purpose.

SRXB-4 In light of the extensive evaluations of post-30 minute steam generator tube rupture consequences, it is not clear that the 30 minute break flow termination time is reasonable.

Please provide additional information to confirm that this assumption is based on observed operator capability, or revise the mass release calculations to incorporate a more realistic break flow termination time. Provide the plant-specific information identified in Requirement (1) of the NRC staff SER approving WCAP-10698 regarding assurance that the necessary actions and times can be taken consistent with those assumed in the SGTR analyses.

SRXB-5 For the SGTR analyses, provide a list of systems, components and instruments that are credited for accident mitigation in the plant specific SGTR EOPs. Specify whether each component is safety grade, consistent with Requirement (4) of the NRC staff SER approving WCAP-10698.

SRXB-6 LR Section 2.8.5.6.2.2.6 evaluates a more realistic SGTR event to confirm that the 30-minute, licensing basis mass release results provide conservative (i.e., acceptably high) inputs to the dose calculations. It appears that this more realistic event shows significant margin to the licensing basis results. The more realistic analysis, however, did not consider (1) uncertainties, (2) a single failure assumption, and (3) conservatism on secondary mass.

Please characterize the impact that these analytic features would have on the predicted results and confirm that, in consideration of these conservatisms, the supplemental thermal-hydraulic analysis would still indicate that the 30-minute licensing basis analysis is still bounding.