ML090830295
| ML090830295 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 03/24/2009 |
| From: | Justin Poole Plant Licensing Branch III |
| To: | Jim Costedio Florida Power & Light Energy Point Beach |
| Poole Justin/DORL/LPL3-1/ 301-415-2048 | |
| References | |
| Download: ML090830295 (2) | |
Text
From:
Justin Poole Sent:
Tuesday, March 24, 2009 11:18 AM To:
'COSTEDIO, JAMES'; 'Flentje, Fritzie'
Subject:
DRAFT RAI questions from the Reactor Systems Branch on the Spent Fuel Pool Amendment
- Jim, By letter dated July 24, 2008 (ADAMS Accession No. ML082240685), as supplemented by letter dated September 19, 2008 (ADAMS Accession No. ML082630114), to the U.S. Nuclear Regulatory Commission (NRC), FPL Energy Point Beach, LLC (FPL, the licensee) submitted a license amendment application to revise the Point Beach Nuclear Plant (PBNP), Units 1 and 2, licensing basis to reflect a revision to the spent fuel pool (SFP) criticality analysis methodology.
The Reactor Systems Branch has reviewed the information provided and determined that in order to complete its evaluation, additional information is required. We would like to discuss the questions, in draft form below, with you in a conference call.
This e-mail aims solely to prepare you and others for the proposed conference call. It does not convey a formal NRC staff position, and it does not formally request for additional information.
Justin C. Poole Project Manager NRR/DORL/LPL3-1 U.S. Nuclear Regulatory Commission (301)415-2048 email: Justin.Poole@nrc.gov
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DRAFT
- 1. (Code validation)
Section 1.4.2 of the application discusses the validation of the SCALE-PC code used in criticality calculations. To allow the staff to evaluate the adequacy of the validation, please provide the following additional information:
a) Discuss and justify the method you used to select the benchmarks identified in Tables 1-1 and 1-2. For example, what parameters were considered to correlate the benchmarks to the systems being analyzed? What ranges were considered for those parameters?
b) Please provide additional details characterizing the benchmarks in terms of the parameters cited in Question 1a above, or submit References 9 through 12 of WCAP-16541-P Revision 2. Currently, the submittal lack sufficient information to evaluate the applicability of the benchmarks to the systems being analyzed.
c) Document and justify the area of applicability for the benchmarks.
d) Describe and justify any statistical and trending analyses performed to support the determination of the bias and bias uncertainty.
e) How did you account for the measurement uncertainties for the benchmarks?
- 2. (Tolerance/Uncertainty calculations) a) Why did you not include the fuel pellet diameter uncertainty in "All-Cell" and "1-out-of-4 5.0 w/o Fresh with no IFBA" when you included it in "1-out-of-4 4.0 w/o Fresh with IFBA" case?
b) How do you determine what manufacturing tolerances to include in the uncertainty study?
c) You appear to assume that the sum of biases and uncertainties for a given configuration remains constant for the different combinations of enrichment, burnup, decay period, and number of IFBAs (for the 1-out-of-4 4.0 w/o Fresh with IFBA). Please substantiate this assumption quantitatively.
- 3. (Bounding fuel design) a) In Section 1.5, you state that the Standard fuel design is bounding for spent fuel and OFA is bounding for fresh. Please quantitatively justify that this assumption is valid for all anticipated storage configurations and burnup/enrichment combinations at Point Beach.
b) In Section 3.2, you state, Westinghouse standard fuel assembly design was modeled as the design basis fuel assembly to represent typical fresh and depleted fuel assemblies residing in all of the fuel assembly storage configurations. Does this contradict the statements in Section 1.5?
c) You also state checkerboard storage configuration utilize the OFA fuel design. What do you mean by checkerboard? Are you referring to the 1 out of 4 configuration?
- 4. (IFBA depletion effect) a) Letter NRC 2008-0071, dated September 19, 2008 provided a response to the staff acceptance review. You state in response to Question 4, that the results demonstrate that including the residual 10B provides sufficient reactivity margin to account for the spectral hardening caused by the presence of IFBA during the depletion. This statement conflicts with NUREG/CR-6760 which states that, the k values become positive for fuel assembly designs containing IFBA rods but remain negative for gadolinia-bearing fuel assembly designs. NUREG/CR-6760 further states that analyses show that there is a negative residual effect for gadolinia-bearing fuel but no such effect for fuel designs with IFBA rods. Please resolve the difference in conclusions between your analysis and that of NUREG/CR-6760.
b) What enrichment was used for the calculations in the table titled, Results of Calculations with IFBA Present During Depletion? Please justify that the results are based on the limiting enrichment and burnup combinations.
- 5. (Soluble Boron Credit)
Letter NRC 2008-0071, dated September 19, 2008 provided a response to the staff acceptance review. Response to Question 2 discussed the effect of parallel accounting method on the boron concentration required for accident conditions. Please justify the effect of parallel accounting method on the boron concentration required for nominal conditions.
DRAFT