ML021140089

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Attachment 4, Faxed on March 25, 2002 (Docket No. 50-416). Draft Questions Re Grand Gulf Nuclear Station License Amendment Request Re Appendix K Measurement Uncertainty Recovery 1.7% Power Uprate
ML021140089
Person / Time
Site: Grand Gulf Entergy icon.png
Issue date: 03/25/2002
From:
Office of Nuclear Reactor Regulation
To:
References
Download: ML021140089 (1)


Text

Grand Gulf Nuclear Station (GGNS)

License Amendment Request re: Appendix K Measurement Uncertainty Recovery 1.7% Power Uprate (Ref. GNRO-2002/00008, dated January 31, 2002)

During review of the proposed changes in the referenced submittal, the NRC staff has prepared the following DRAFT questions for discussion and clarification during a forthcoming telephone conference:

(1) The Staff SER on Caldon Topical Reports ER-1 57P stated that in addition to the guidelines outlined in ER-1 57P and ER- 80P, four additional requirements shall be addressed by licensees referencing ER-157P in their request for power uprate. The staff guidelines for addressing those additional requirements are provided in section I of attachment 1 to the NRC Regulatory Issue Summary (RIS) 2002-03, dated January 31, 2002. Entergy submittal addressed only one of the four additional requirements distributed in section 4.2.2, section 4.2.3, and section 4.2.6. Detail information addressing each of the four requirements and the applicable RIS guidelines are needed to complete the staff review of Entergy's power uprate request for GGNS.

(2) RIS guideline (item E in section I) requested licensees to provide a plant specific calculation of total power measurement uncertainty, explicitly identifying all parameters and their individual contribution to the power measurement uncertainty. The applicable discussion in section1.4 of the G.E. Safety Analysis Report does not provide the information requested in the RIS guideline. Also, section 4.2.5 in attachment 1 of the Entergy's submittal stated, that Caldon has completed the GGNS LEFM Check Plus system uncertainty calculation indicating a mass flow inaccuracy of <0.3% of rated flow for the site-specific installation. Please submit this calculation for staff review making sure that the calculation follows ER-80P guidelines, is based on the accepted setpoint methodology as stated in the third requirement of the staff SER, and provides bases for Entergy's statement in section 4.2.7 and G.E. Safety Analysis Report statements in section 1.4.

(3) G.E. Safety Analysis Report in section 5.3 stated that, in some cases, changes in the allowable value(AV) and nominal trip setpoint (NTSP) of instrumentation setting will occur in the measured units. The G.E. safety analysis also stated in the same section that, the corresponding setpoint in terms of steam flow is decreased to approximately 138% of the TPO rated steam flow. Please confirm that the safety system instrumentation NTSPs and Avs included in the plant Technical Specifications do not need revision due to the proposed power uprate.

(4) For an inoperable LEFM, section 4.2.2 in attachment 1 and comment column in attachment 4 state that, "...the reactor thermal power will be administratively controlled at a level consistent with the accuracy of the available instrumentation until such time as the LEFM system is returned to an operable status." The staff understands that, in case of an inoperable LEFM, the "available instrumentation" will be the venturi whose measurement uncertainty is the basis of the current licensed thermal power of 3833 MWt. Please explain why the contingency plan does not require plant operation at 3833 Mwt. instead of "consistent with the accuracy of the available instrumentation."

Attachment 4