ML19296C273
| ML19296C273 | |
| Person / Time | |
|---|---|
| Site: | 07109228 |
| Issue date: | 10/23/2019 |
| From: | William Allen Storage and Transportation Licensing Branch |
| To: | Lamb S GE Hitachi Nuclear Energy |
| Allen W | |
| References | |
| EPID L-2019-LLA-0168 | |
| Download: ML19296C273 (5) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 23, 2019 Mr. Shawn Lamb Engineering Manager GE Hitachi Nuclear Energy Americas, LLC 3901 Castle Hayne Road Wilmington, NC 28401
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR REVIEW OF THE MODEL NO. 2000 PACKAGE
Dear Mr. Lamb:
By letter dated July 31, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19212A593), GE-Hitachi Nuclear Energy Americas, LLC submitted an application to amend Certificate of Compliance No. 9228 for the Model No. 2000 package to reintroduce GE 10x10 Boiling Water Reactor irradiated fuel as part of the approved content. To assist with our review, the U.S. Nuclear Regulatory Commission staff (the staff) needs the information identified in the enclosure to this letter. Discussion of this request for additional information (RAI) and a response date occurred on October 21, 2019.
We request that you provide this information by November 22, 2019. Inform us at your earliest convenience, but no later than November 15, 2019, if you are not able to provide the information by that date. If you are unable to provide a response by November 22, 2019, please propose a new submittal date with the reasons for the delay.
Please reference Docket No. 71-9228 and EPID No. L-2019-LLA-0168 in future correspondence related to this amendment request. The staff is available to discuss these questions as well as your proposed responses. If you have any questions regarding this matter, feel free to contact me at (301) 415-6877.
Sincerely,
/RA/
Chris Allen, Project Manager Storage and Transportation Licensing Branch Division of Fuel Management Office of Nuclear Material Safety and Safeguards Docket No. 71-9228 EPID No. L-2019-LLA-0168
S. Lamb 2
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR REVIEW OF THE MODEL NO. 2000 PACKAGE DOCUMENT DATE: October 23, 2019
Enclosure:
Request for Additional Information DISTRIBUTION: SFST r/f RPowell, RI SWalker, RII MKunowski, RIII JKatanic, RIV DMarcano G:\\SFST\\Allen\\Part 71\\GE-2000\\RAI\\Letter.docx ADAMS No.: ML19296C273 OFC:
DFM DFM DFM DFM NAME:
WAllen SFigueroa via e-mail DForsyth DBarto via e-mail DATE:
10/10/19 10/15/19 10/15/19 10/15/19 OFC:
DFM DFM NAME:
JSmith for TTate DDoyle DATE:
10/16/19 10/23/19 OFFICIAL RECORD COPY
Enclosure Request for Additional Information Docket No. 71-9228 Model No. 2000 Package By letter dated July 31, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19212A593), GE-Hitachi Nuclear Energy Americas, LLC submitted an application to amend Certificate of Compliance No. 9228 for the Model No. 2000 package to reintroduce GE 10x10 Boiling Water Reactor irradiated fuel as part of the approved content.
This RAI letter identifies information needed by the staff in connection with its review of the application. NUREG-1617, Standard Review Plan for Transportation Packages for Spent Nuclear Fuel," was used by the staff in its review of the application.
Each individual RAI describes information needed by the NRC staff to complete its review of the application to determine whether the applicant has demonstrated compliance with the regulatory requirements.
Shielding Review 5.1 Revise the safety analysis report (SAR) to clearly identify the source strength shielding model assumptions.
SAR section 5.3.1.1 states, on page 5-7, For the segmented irradiated fuel content, the NCT source geometry is a single 5.3-inch line source across which the photon and neutron sources are distributed uniformly. Staff inferred that this statement meant the applicant modeled the entire irradiated fuel source strength in a 5.3-inch line segment.
The applicant confirmed the veracity of this assumption during a telephone call on September 24, 2019 (ML19269E524). The applicant should revise the SAR to clearly identify the source strength associated with the line segment described in the SAR.
This information is needed to verify compliance with Title 10 of the Code of Federal Regulations (10 CFR) 71.47(a).
Criticality Review 6.1 Justify the height chosen for the contents in the criticality model.
The SAR states that fuel rod contents are modeled as the maximum height that would fit within the high performance insert internal cavity height. However, there are no constraints on fuel rod height, and actual rod segments may be much shorter than the heights considered. Using a shorter fuel column height for all the rod segments in the package may result in a higher keff for the same mass of fuel, even at the same H/235U ratios considered, due to a lower neutron leakage geometry. The applicant should consider shorter height fuel rods, for the 235U mass limit requested, in its criticality model of the package and revise the application if necessary.
This information is needed to ensure that the package meets the criticality safety requirements of 10 CFR 71.55 and §71.59.
2 6.2 Revise the benchmarking evaluations in the application to include an adequate range of experiments to cover the enrichment of the fuel in the Model No. 2000 criticality model.
Alternatively, describe the methods used to extrapolate the bias and bias uncertainty of the criticality code beyond the range of applicability of the benchmarking analysis, and include an additional uncertainty to account for this extrapolation.
The application discussed the experiments selected to benchmark the MCNP6 Version 1.0 criticality code and continuous energy ENDF/B-VII.1 cross section library for use in modeling the GE 2000 package with spent iron-chromium-aluminum clad fuel rod segments. Although the amendment is requesting fuel enriched up to 6.0 weight percent 235U, experiments selected by the applicant for benchmarking are from only two series. In addition, the applicant included only two different enrichments: 2.35 and 4.306 weight percent 235U. There are many additional experiments available in the International Criticality Safety Benchmark Evaluation Project Handbook (ICSBEP, OEDC-NEA, 2018) which would be applicable to the GE 2000 system being modeled (i.e., low enriched uranium oxide rods moderated by water). While most of these experiments include uranium enriched to less than 5.0 weight percent, there are a small number above 5.0 weight percent enrichment which would be applicable to the system, and these experiments would extend the range of applicability of the benchmarking analysis to cover the 6.0 weight percent fuel modeled in the application. Specifically, LEU-COMP-THERM (LCT) -070, -075, -078, -080, -085, -094, -096, -097, and -098 from the ICSBEP Handbook all contain uranium oxide enriched to greater than 5.0 weight percent, and these experiments may be applicable to the GE 2000 system. Absent additional experiments to extend the range of applicability, the applicant should include additional margin in the calculated upper subcritical limit to account for uncertainty due to extension beyond the range of applicability of the benchmarking analysis.
This information is needed to ensure that the package meets the criticality safety requirements of 10 CFR 71.55 and §71.59.
6.3 Revise the application to correct inconsistencies, both in the number of experiments included and the enrichments of experiments, in the benchmarking analysis.
Section 6.8.1 of the SAR states that the benchmarking analysis included 69 critical experiments. However, Table 6.9.2-1 of the SAR only shows results from 36 experiments.
Additionally, Section 6.8.1 of the SAR states that the enrichment of the selected critical experiments ranged from 2.35 to 4.92 weight percent 235U. However, the maximum enrichment shown in the results in Table 6.9.2-1 is 4.306 weight percent 235U. The application should be revised to correct these inconsistencies.
This information is needed to ensure that the package meets the criticality safety requirements of 10 CFR 71.55 and §71.59.
3 6.4 Revise the application to demonstrate that the keff results used to determine the code bias and bias uncertainty in the benchmarking analysis are normally distributed.
The applicant used two methods from NUREG/CR-6361, Criticality Benchmark Guide for Light-Water-Reactor Fuel in Transportation and Storage Packages, to determine the code bias and bias uncertainty. NUREG/CR-6361 assumes normally distributed keff values for using these two methods. In addition, NUREG/CR-6361 requires that normality be demonstrated by a statistical test. However, the application does not contain a statistical test demonstrating the normality of the keff values. The application should be revised to include a demonstration of normality for the reported keff values in the benchmarking analysis.
This information is needed to ensure that the package meets the criticality safety requirements of 10 CFR 71.55 and §71.59.
6.5 Justify the exclusion of several critical experiments from the selected experiment series used in the benchmarking analysis of SAR Section 6.8 or revise the application to include these experiments.
Table 6.9.2-1 of the SAR shows that experiments used in the benchmarking analysis were selected from LCT-010 and -017 of the ICSBEP Handbook. However, cases 14-19 and 28-30 of LCT-010 and case 1-14 of LCT-017 were excluded. The application should be revised to include these experiments, or the applicant should justify excluding them from the benchmarking analysis.
This information is needed to ensure that the package meets the criticality safety requirements of 10 CFR 71.55 and §71.59.