RAIO-0818-61622, LLC Response to NRC Request for Additional Information No. 52 (Erai No. 8855) on the NuScale Design Certification Application
| ML18241A397 | |
| Person / Time | |
|---|---|
| Site: | NuScale |
| Issue date: | 08/29/2018 |
| From: | Wike J NuScale |
| To: | Document Control Desk, Office of New Reactors |
| References | |
| RAIO-0818-61622 | |
| Download: ML18241A397 (4) | |
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Powe, f oe o ll humonhnd August29,2018 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 RAI 0-0818-61622 Docket No.52-048
SUBJECT:
NuScale Power, LLC Response to NRC Request for Additional Information No.
52 (eRAI No. 8855) on the NuScale Design Certification Application
REFERENCES:
- 1. U.S. Nuclear Regulatory Commission, "Request for Additional Information No. 52 (eRAI No. 8855)," dated June 02, 2017
- 2. NuScale Power, LLC Response to NRC "Request for Additional Information No. 52 (eRAI 8855)," dated April 3, 2018 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 NuScale's response to the following RAI Question from NRC eRAI No. 8855:
- 03.06.02-14 The response to RAI Question 03.06.02-13 was previously provided in Reference 2.
This letter and the enclosed response make no new regulatory commitments and no revisions to any existing regulatory commitments.
If you have any questions on this response, please contact Marty Bryan at 541-452-7172 or at mbryan@nuscalepower.com.
Sincerely, JJI:~~
Manager, Licensing NuScale Power, LLC Distribution: Gregory Cranston, NRC, OWFN-8G9A Samuel Lee, NRC, OWFN-8G9A Marieliz Vera, NRC, OWFN-8G9A : NuScale Response to NRC Request for Additional Information eRAI No. 8855 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com
RAIO-0818-61622 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com :
NuScale Response to NRC Request for Additional Information eRAI No. 8855
Response to Request for Additional Information Docket No.52-048 eRAI No.: 8855 Date of RAI Issue: 06/02/2017 NRC Question No.: 03.06.02-14 To ensure the compliance with GDC 4 requirements for protecting SSCs important to safety against the dynamic effects of postulated pipe ruptures, the NRC staff in SRP Section 3.6.2 Section III.2.A provides its guidance for evaluating the dynamic response of the fluid system piping when pipe ruptures are postulated. Specifically, SRP Section 3.6.2 Section III.2.A states that an analysis of the dynamic response of the pipe run or branch should be performed for each longitudinal and circumferential postulated piping break. The loading condition (e.g., internal pressure, temperature, etc.) of a pipe run or branch, prior to the postulated rupture, should be used in the evaluation for postulated breaks. For piping pressurized during operation at power, the initial condition should be greater of the contained energy at hot standby or at 102 percent power. The NRC staff found no information (or pointer) in FSAR Section 3.6 which addresses the initial condition assumed for evaluating the dynamic response of the postulated breaks.
Clarify the piping system initial conditions assumed in the pipe motion and dynamic effects of postulated breaks analysis and compare this with the NRC guidance as delineated in SRP Section 3.6.2 Section III.2.A.
NuScale Response:
FSAR Table 3.6-4, NuScale Power Module Piping Systems Design and Operating Parameters, provides the initial conditions assumed for dynamic response to pipe breaks. The initial conditions are based on full power operation rather than hot standby operation, for which the NuScale equivalent is referred to as hot shutdown. During hot shutdown, main steam system (MSS) pressure and temperature are approximately 300 psia and 420ºF, and primary pressure and temperature are approximately 1850 psia and 420ºF. For MSS HELBs, full power operating conditions produce higher calculated thrust loads that bound those at hot shutdown. For chemical and volume control system (CVCS) and reactor coolant system (RCS) HELBs, calculated thrust loads at normal operating conditions do not bound those at hot shutdown, because the jet thrust load is dependent, in part, on the thrust coefficient, which is 2.0 for nonflashing blowdown vs. 1.26 for steam. The higher subcooling margin at hot shutdown conditions could result in a nonflashing blowdown. However, using full power operation rather than hot shutdown conditions does not change the conclusions of whether an RCS line in the NuScale Nonproprietary
CNV will whip or whether its trajectory impacts a vulnerable target. In the area under the bioshield, HELBs are precluded by design to satisfy BTP 3-4 B.A.(ii) and (iii) break exclusion criteria. For CVCS HELBs in the RXB, the most limiting (maximum pressure and temperature) system conditions for pipe whip of various pipe segments are considered, and are outlined in FSAR Table 3.6-4.
Impact on DCA:
There are no impacts to the DCA as a result of this response.
NuScale Nonproprietary