ML24348A130
| ML24348A130 | |
| Person / Time | |
|---|---|
| Site: | 05200050 |
| Issue date: | 12/13/2024 |
| From: | Shaver M NuScale |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| Shared Package | |
| ML24348A129 | List: |
| References | |
| RAIO-176409 | |
| Download: ML24348A130 (1) | |
Text
RAIO-176409 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com December 13, 2024 Docket No.52-050 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738
SUBJECT:
NuScale Power, LLC Response to NRC Request for Additional Information No. 037 (RAI-10357 R1) on the NuScale Standard Design Approval Application
REFERENCE:
NRC Letter to NuScale, Request for Additional Information No. 037 (RAI-10357 R1), dated October 17, 2024 The purpose of this letter is to provide the NuScale Power, LLC (NuScale) response to the referenced NRC Request for Additional Information (RAI).
The enclosure to this letter contains the NuScale response to the following RAI question from NRC RAI-10357 R1:
15.1.1-8, NonLOCA.LTR-53 is the proprietary version of the NuScale Response to NRC RAI No. 037 (RAI-10357 R1, Question 15.1.1-8, NonLOCA.LTR-53). NuScale requests that the proprietary version be withheld from public disclosure in accordance with the requirements of 10 CFR § 2.390. The enclosed affidavit (Enclosure 3) supports this request. Enclosure 2 is the nonproprietary version of the NuScale response.
This letter makes no regulatory commitments and no revisions to any existing regulatory commitments.
If you have any questions, please contact Amanda Bode at 541-452-7971 or at abode@nuscalepower.com.
I declare under penalty of perjury that the foregoing is true and correct. Executed on December 13, 2024.
Sincerely, Mark W. Shaver Director, Regulatory Affairs NuScale Power, LLC
RAIO-176409 Page 2 of 2 12/13/2024 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com Distribution:
Mahmoud Jardaneh, Chief New Reactor Licensing Branch, NRC Getachew Tesfaye, Senior Project Manager, NRC Stacy Joseph, Senior Project Manager, NRC
- NuScale Response to NRC Request for Additional Information RAI-10357 R1, Question 15.1.1-8, NonLOCA.LTR-53, Proprietary Version : NuScale Response to NRC Request for Additional Information RAI-10357 R1, Question 15.1.1-8, NonLOCA.LTR-53, Nonproprietary Version : Affidavit of Mark W. Shaver, AF-176410
RAIO-176409 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com NuScale Response to NRC Request for Additional Information RAI-10357 R1, Question 15.1.1-8, NonLOCA.LTR-53, Proprietary Version
RAIO-176409 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com NuScale Response to NRC Request for Additional Information RAI-10357 R1, Question 15.1.1-8, NonLOCA.LTR-53, Nonproprietary Version
Response to Request for Additional Information Docket: 052000050 RAI No.: 10357 Date of RAI Issue: 10/17/2024 NRC Question No.: 15.1.1-8, NonLOCA.LTR-53 Issue Table 7-7 of the Non-LOCA LTR states that an applicant implementing the methodology will perform sensitivity studies on initial feedwater (FW) temperature and initial steam generator (SG) pressure in order to identify the limiting MCHFR for the decrease in feedwater temperature event. The applicant provided for NRC staff audit (ML23067A300) the sensitivity studies to support the standard design approval application for the NPM-20. However, the staff noted that the initial feedwater temperature and initial steam generator pressure were varied simultaneously in these studies. The staff also noted that these studies varied bypass of the high power rate trip and operation of the CRA regulating bank. Because these four parameters are varied simultaneously, the impact of any individual change on MCHFR cannot be determined. As such, the NRC staff cannot conclude that initial SG pressure and FW temperature were varied to identify the limiting MCHFR consistent with the Non-LOCA LTR evaluation model.
During the staffs audit, the applicant stated that examining biased-high initial feedwater temperature (( 2(a),(c) that is evaluated in the decrease in feedwater temperature event. The staff considers evaluation of cases with biased-high initial feedwater temperature to be a necessary step to ensure that the limiting MCHFR is identified, but it is not clear whether ((
}}
2(a),(c) will minimize margin to acceptance criteria. During the audit discussion, the applicant also stated that maintaining consistent steam pressure allows comparison of the cooldown effect driven by the initiating event (i.e., decreasing feedwater temperature). However, NRC staff does not consider that studying the cooldown effect with consistent initial SG pressure precludes variation of initial SG pressure in a separate set of cases in order to assure that the limiting MCHFR is identified. The staff also noted additional calculations that deviate from the methodologies defined in the Non-LOCA LTR. NuScale Nonproprietary NuScale Nonproprietary
The audited calculation that supports the single CRA withdrawal evaluation, uses a (( }} 2(a),(c). However, Table 7-68 of the Non-LOCA LTR specifies that a biased-low initial fuel temperature should be used. The audited calculation does not specify that assuming a (( }} 2(a),(c) deviates from the LTR methodology nor does it provide an acceptable justification for deviation from the proposed NPM-20 licensing basis. The audited calculation also states that using a biased-low initial fuel temperature is more conservative. Information Requested
- 1. Provide results of sensitivity studies that vary initial feedwater temperature independently of other parameters to demonstrate that the limiting MCHFR is identified for the decrease in feedwater temperature event.
- 2. Provide results of sensitivity studies that vary initial steam generator pressure independently of other parameters to demonstrate that the limiting MCHFR is identified for the decrease in feedwater temperature event.
- 3. Provide revised calculations for the single CRA withdrawal event with initial fuel temperature assumptions that bias initial fuel temperature consistent with the Non-LOCA LTR methodology, or provide appropriate justification for use of the ((
}} 2(a),(c) initial fuel temperature and modify the FSAR to describe the deviation from the LTR methodology. NuScale Response: Parts 1 and 2 EC-104467, Revision 0, NPM-20 Decrease in Feedwater Temperature Transient Analysis (previously provided in the Chapter 15 electronic reading room (eRR) for NRC audit), evaluates biased initial feedwater (FW) temperature and initial steam generator (SG) pressure conditions to determine minimum critical heat flux ratio (MCHFR) conditions in accordance with Table 7-7 of TR-0516-49416-P, Revision 4, Non-Loss-of-Coolant Accident Analysis Methodology. The stated NRC question is that initial FW temperature and initial SG pressure in EC-104467, Revision 0, are not varied individually, but varied in conjunction with other parameters that could make it difficult to determine their individual effect on MCHFR. EC-104467, Revision 1, NPM-20 Decrease in Feedwater Temperature Transient Analysis, has been issued to address the NRC question and is provided in the eRR with this response. The following sections of EC-104467, Revision 1, are relevant to address the NRC question: NuScale Nonproprietary NuScale Nonproprietary
(( }}2(a),(c) In conclusion, EC-104467, Revision 1, contains the requisite sensitivity studies for initial FW temperature and initial SG pressure in accordance with Table 7-7 of TR-0516-49416-P, Revision 4. The parameters are varied both individually and along with combinations of other parameters and the results are used to identify the limiting case for MCHFR. Part 3 Table 7-68 of TR-0516-49416-P, Revision 4, Non-Loss-of-Coolant Accident Analysis Methodology, identifies the initial conditions, biases, and conservatisms associated with the single control rod assembly withdrawal event. For the initial fuel temperature, Table 7-68 indicates that a low bias is used. NuScale Nonproprietary NuScale Nonproprietary
EC-0000-8579, Revision 1, Control Rod Misoperation Transient Analysis, (previously provided in the eRR for NRC audit) implements the parameter assumptions from Table 7-68 of TR-0516-49416-P, Revision 4. ((
}}2(a),(c)
NuScale has reviewed the inputs and outputs associated with EC-0000-8579 and confirms that the initial fuel temperature is consistent with bias in the low direction. No calculation revisions are necessary due to this question as the calculation correctly implements the bias identified by Table 7-68 of TR-0516-49416-P. Impact on US460 SDAA: There are no impacts to the US460 SDAA as a direct result of this response. However, the calculation revision described in this response impacts FSAR Section 15.1.1. The revisions to FSAR Section 15.1.1 to incorporate the calculation results will be included in FSAR Revision 2. One impact of note is that the revised calculation modified the treatment of reactivity feedback. In the prior revision, the most limiting time in cycle (i.e., end of cycle) was assumed, resulting in the use of the most negative Doppler temperature coefficient (DTC) and most negative moderator temperature coefficient (MTC). In the current revision, the most positive DTC and most negative MTC are used. This combination of DTC and MTC, although not representative of an actual time in cycle, is conservative for the power response. FSAR Section 15.1.1.3.2 is revised as follows: NuScale Nonproprietary NuScale Nonproprietary
The most positive Doppler temperature coefficient (DTC) and most negative moderator temperature coefficient (MTC) are used to provide a limiting power response.The most limiting end of cycle (EOC) reactivity feedback is used to provide a limiting power response. Impact on Topical Report: There are no impacts to Topical Report TR-0516-49416, Non-Loss-of-Coolant Accident Analysis Methodology, as a result of this response. NuScale Nonproprietary NuScale Nonproprietary
RAIO-176409 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com Affidavit of Mark W. Shaver, AF-176410
AF-176410 Page 1 of 2
NuScale Power, LLC AFFIDAVIT of Mark W. Shaver I, Mark W. Shaver, state as follows: (1) I am the Director of Regulatory Affairs of NuScale Power, LLC (NuScale), and as such, I have been specifically delegated the function of reviewing the information described in this Affidavit that NuScale seeks to have withheld from public disclosure, and am authorized to apply for its withholding on behalf of NuScale. (2) I am knowledgeable of the criteria and procedures used by NuScale in designating information as a trade secret, privileged, or as confidential commercial or financial information. This request to withhold information from public disclosure is driven by one or more of the following: (a) The information requested to be withheld reveals distinguishing aspects of a process (or component, structure, tool, method, etc.) whose use by NuScale competitors, without a license from NuScale, would constitute a competitive economic disadvantage to NuScale. (b) The information requested to be withheld consists of supporting data, including test data, relative to a process (or component, structure, tool, method, etc.), and the application of the data secures a competitive economic advantage, as described more fully in paragraph 3 of this Affidavit. (c) Use by a competitor of the information requested to be withheld would reduce the competitors expenditure of resources, or improve its competitive position, in the design, manufacture, shipment, installation, assurance of quality, or licensing of a similar product. (d) The information requested to be withheld reveals cost or price information, production capabilities, budget levels, or commercial strategies of NuScale. (e) The information requested to be withheld consists of patentable ideas. (3) Public disclosure of the information sought to be withheld is likely to cause substantial harm to NuScales competitive position and foreclose or reduce the availability of profit-making opportunities. The accompanying Request for Additional Information response reveals distinguishing aspects about the response by which NuScale develops its NuScale Power, LLC Response to NRC Request for Additional Information (RAI No. 10357 R1, Question 15.1.1-8, NonLOCA.LTR-53) on the NuScale Standard Design Approval Application. NuScale has performed significant research and evaluation to develop a basis for this response and has invested significant resources, including the expenditure of a considerable sum of money. The precise financial value of the information is difficult to quantify, but it is a key element of the design basis for a NuScale plant and, therefore, has substantial value to NuScale. If the information were disclosed to the public, NuScales competitors would have access to the information without purchasing the right to use it or having been required to undertake a similar expenditure of resources. Such disclosure would constitute a misappropriation of NuScales intellectual property, and would deprive NuScale of the opportunity to exercise its competitive advantage to seek an adequate return on its investment. (4) The information sought to be withheld is in the enclosed response to NRC Request for Additional Information RAI 10357 R1, Question 15.1.1-8, NonLOCA.LTR-53. The enclosure contains the designation Proprietary at the top of each page containing proprietary information. The information considered by NuScale to be proprietary is identified within double braces, (( }} in the document.
AF-176410 Page 2 of 2 (5) The basis for proposing that the information be withheld is that NuScale treats the information as a trade secret, privileged, or as confidential commercial or financial information. NuScale relies upon the exemption from disclosure set forth in the Freedom of Information Act (FOIA), 5 USC § 552(b)(4), as well as exemptions applicable to the NRC under 10 CFR §§ 2.390(a)(4) and 9.17(a)(4). (6) Pursuant to the provisions set forth in 10 CFR § 2.390(b)(4), the following is provided for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld: (a) The information sought to be withheld is owned and has been held in confidence by NuScale. (b) The information is of a sort customarily held in confidence by NuScale and, to the best of my knowledge and belief, consistently has been held in confidence by NuScale. The procedure for approval of external release of such information typically requires review by the staff manager, project manager, chief technology officer or other equivalent authority, or the manager of the cognizant marketing function (or his delegate), for technical content, competitive effect, and determination of the accuracy of the proprietary designation. Disclosures outside NuScale are limited to regulatory bodies, customers and potential customers and their agents, suppliers, licensees, and others with a legitimate need for the information, and then only in accordance with appropriate regulatory provisions or contractual agreements to maintain confidentiality. (c) The information is being transmitted to and received by the NRC in confidence. (d) No public disclosure of the information has been made, and it is not available in public sources. All disclosures to third parties, including any required transmittals to NRC, have been made, or must be made, pursuant to regulatory provisions or contractual agreements that provide for maintenance of the information in confidence. (e) Public disclosure of the information is likely to cause substantial harm to the competitive position of NuScale, taking into account the value of the information to NuScale, the amount of effort and money expended by NuScale in developing the information, and the difficulty others would have in acquiring or duplicating the information. The information sought to be withheld is part of NuScales technology that provides NuScale with a competitive advantage over other firms in the industry. NuScale has invested significant human and financial capital in developing this technology and NuScale believes it would be difficult for others to duplicate the technology without access to the information sought to be withheld. I declare under penalty of perjury that the foregoing is true and correct. Executed on December 13, 2024. Mark W. Shaver}}