ML18095B049
| ML18095B049 | |
| Person / Time | |
|---|---|
| Site: | NuScale |
| Issue date: | 04/05/2018 |
| From: | NRC |
| To: | NRC/NRO/DNRL/LB1 |
| References | |
| Download: ML18095B049 (4) | |
Text
NuScaleDCRaisPEm Resource From: Chowdhury, Prosanta Sent: Thursday, April 5, 2018 3:10 PM To: Request for Additional Information Cc: Lee, Samuel; Cranston, Gregory; Franovich, Rani; Karas, Rebecca; Burja, Alexandra; NuScaleDCRaisPEm Resource
Subject:
Request for Additional Information No. 409 eRAI No. 9509 (15.04.02)
Attachments: Request for Additional Information No. 409 (eRAI No. 9509).pdf Attached please find NRC staffs request for additional information (RAI) concerning review of the NuScale Design Certification Application.
The NRC Staff recognizes that NuScale has preliminarily identified that the response to one or more questions in this RAI is likely to require greater than 60 days. NuScale is expected to provide a schedule for the RAI response by email within 14 days.
If you have any questions, please contact me.
Thank you.
Prosanta Chowdhury, Project Manager Licensing Branch 1 (NuScale)
Division of New Reactor Licensing Office of New Reactors U.S. Nuclear Regulatory Commission 301-415-1647 1
Hearing Identifier: NuScale_SMR_DC_RAI_Public Email Number: 440 Mail Envelope Properties (BN7PR09MB260917047C0A8326CF5654189EBB0)
Subject:
Request for Additional Information No. 409 eRAI No. 9509 (15.04.02)
Sent Date: 4/5/2018 3:10:10 PM Received Date: 4/5/2018 3:10:16 PM From: Chowdhury, Prosanta Created By: Prosanta.Chowdhury@nrc.gov Recipients:
"Lee, Samuel" <Samuel.Lee@nrc.gov>
Tracking Status: None "Cranston, Gregory" <Gregory.Cranston@nrc.gov>
Tracking Status: None "Franovich, Rani" <Rani.Franovich@nrc.gov>
Tracking Status: None "Karas, Rebecca" <Rebecca.Karas@nrc.gov>
Tracking Status: None "Burja, Alexandra" <Alexandra.Burja@nrc.gov>
Tracking Status: None "NuScaleDCRaisPEm Resource" <NuScaleDCRaisPEm.Resource@nrc.gov>
Tracking Status: None "Request for Additional Information" <RAI@nuscalepower.com>
Tracking Status: None Post Office: BN7PR09MB2609.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 675 4/5/2018 3:10:16 PM Request for Additional Information No. 409 (eRAI No. 9509).pdf 15967 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:
Recipients Received:
Request for Additional Information No. 409 (eRAI No. 9509)
Issue Date: 04/05/2018 Application
Title:
NuScale Standard Design Certification 048 Operating Company: NuScale Power, LLC Docket No.52-048 Review Section: 15.04.02 - Uncontrolled Control Rod Assembly Withdrawal at Power Application Section: FSAR Section 15.4.2 QUESTIONS 15.04.02-3 General Design Criterion (GDC) 13, "Instrumentation and control," in Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix A, requires the provision of instrumentation to monitor variables and systems over their anticipated ranges of normal operation, including the effects of anticipated operational occurrences (AOOs), and of appropriate controls to maintain listed variables and systems within prescribed operating ranges. NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition,"
(SRP) Section 15.4.2, "Uncontrolled Control Rod Assembly Withdrawal at Power," provides the staff guidance in determining compliance with GDC 13, among several other GDC, and guides the reviewer to evaluate the sequence of events, including actuations of protection systems, to determine whether the sequence of events is justified, based upon the expected values of the relevant monitored parameters and instrument indications.
The May 24, 2017, response to RAI 8764 (ADAMS Accession No. ML17144A450) provided FSAR markups for FSAR Section 15.2, "Uncontrolled Control Rod Assembly Withdrawal at Power," and the related results. The markups of FSAR Table 15.4-3, "Sequence of Events (15.4.2 Uncontrolled Control Rod Assembly Withdrawal at Power)," show that the high reactor power limit is reached at 186 seconds. FSAR Section 15.4.2.3.3 also states that the high hot leg temperature limit, the high pressurizer limit, and high power limit are all reached during the reactor trip delay time.
However, the revised Figure 15.4-7, "Reactor Power (15.4.2 Uncontrolled Control Rod Assembly Withdrawal at Power)," shows that the reactor power remains under the high reactor power limit of 120 percent, which is consistent with the results presented in engineering calculation (EC)-0000-1999, "Uncontrolled Control Rod Assembly Withdrawal At Power Transient Analysis," the calculation supporting FSAR Section 15.2, which the staff audited. Therefore, update FSAR Table 15.4-3 and FSAR Section 15.4.2.3.3 to reflect the fact that the high reactor power limit is not reached.
15.04.02-4 GDC 10, "Reactor design," requires that the reactor core and associated coolant, control, and protection systems shall be designed with appropriate margin to assure that specified acceptable fuel design limits (SAFDLs) are not exceeded during any condition of normal operation, including the effects of AOOs. SRP Section 15.4.2 provides the staff guidance in determining compliance with GDC 10, among several other GDC, and guides the reviewer to ascertain that a full range of AOO conditions are analyzed and that the AOO calculation models
are adequate. In addition, the specific acceptance criteria to ensure the SAFDLs are met include the departure from nucleate boiling ratio (for NuScale, minimum critical heat flux ratio
[MCHFR]) being met and fuel centerline temperatures not exceeding the melting point.
FSAR Tier 2, Section 15.4.2.3.2, and Table 15.4-4, "Key Inputs for Limiting MCHFR Case (15.4.2 Uncontrolled CRA Withdrawal at Power)," discuss and provide input parameters and initial conditions for the limiting minimum critical heat flux ratio (MCHFR) case. FSAR Tier 2, Section 15.4.2.3.3, discusses the results for the limiting MCHFR and reactor coolant system pressure cases. However, there is no discussion of the initial conditions or results of the maximum linear heat generation rate (LHGR) case, which provides conclusions regarding the fuel centerline melting acceptance criterion, aside from the LHGR value itself. To enable the staff to ensure that the limiting results for fuel centerline temperature have been identified, update the FSAR to include the key initial conditions and a high-level discussion of the event results for the limiting LHGR case.