|
---|
Category:Letter
MONTHYEARML23180A1512023-06-29029 June 2023 LLC, Request for Exemption to the Reporting Requirements of 10 CFR 50.46(a)(3) ML21102A3072021-04-15015 April 2021 OEDO-21-00155 - Lessons-Learned from the Design Certification Review of the NuScale Power, LLC, Small Modular Reactor ML21050A4312021-02-19019 February 2021 LLC - Lessons-Learned from the Design Certification Review of the NuScale Power, LLC Small Modular Reactor ML20247J5642020-09-11011 September 2020 Standard Design Approval for the NuScale Power Plant Based on the NuScale 600 Standard Plant Design Certification Application ML20231A8042020-08-28028 August 2020 Final Safety Evaluation Report for the NuScale Standard Plant Design ML20224A4602020-08-25025 August 2020 OEDO-20-00292-Response to the Advisory Committee on Reactor Safeguards Letter on NuScale Power, LLC, Report on the Safety Aspects of the NuScale Small Modular Reactor ML20231A5982020-08-25025 August 2020 OEDO-20-00285_NuScale Area of Focus - Boron Redistribution ML20210M8902020-07-29029 July 2020 Area of Focus - Boron Redistribution ML20195A5872020-07-13013 July 2020 LLC - Submittal of Draft Operator Licensing and Examination Standard for NuScale Small Modular Reactors ML20195C7662020-07-13013 July 2020 LLC Request for Standard Design Approval Based on the NuScale Standard Plant Design Certification Application ML20192A3262020-07-10010 July 2020 LLC, Submittal of Environmental Report: Revision Status ML20198M3932020-07-0202 July 2020 LLC Submittal of Revised Packing Slip for Submittal of the NuScale Standard Plant Design Certification Application, Revision 4.1, Dated June 19, 2020 ML20174A3472020-07-0101 July 2020 OEDO-20-00220 - Area of Focus - Probabilistic Risk Assessment and Emergency Core Cooling System Valve Performance ML20184A2872020-07-0101 July 2020 LLC Submittal of Presentation Materials Entitled ACRS Full Committee Presentation: NuScale Topic - Boron Redistribution and General Design Criterion 33, PM-0720-70785, Revision 0 ML20181A4322020-06-22022 June 2020 Final SER for NuScale TR-0516-49416 NON-Loss-of-Coolant Analysis Model, Rev 3 (Letter) ML20181A2702020-06-22022 June 2020 Final SER for NuScale TR-0516-49422 Loss-of-Coolant Analysis Model, Rev 2 (Letter) ML20198M3922020-06-19019 June 2020 LLC - Submittal of the NuScale Standard Plant Design Certification Application, Revision 4.1 ML20171A7312020-06-19019 June 2020 LLC, Submittal of Riser Flow Hole Methodology and Associated Changes to Final Safety Analysis Report Incorporating Its Use ML20157A2232020-06-0303 June 2020 Letter to NuScale Requesting -A for TR-0716-50350 ML20150C5172020-05-29029 May 2020 LLC Submittal of Presentation Materials Entitled NRC Public Meeting Presentation: Boron Redistribution and Associated Design and DCA Changes, PM-0620-70336, Revision 0 ML20150E1772020-05-29029 May 2020 LLC - Submittal of Presentation Materials Entitled ACRS Full Committee Presentation: NuScale Topic - Extended Dhrs Operation and RCS Boron Redistribution (Closed Session), PM-0620-70243, Revision 0 ML20150C8812020-05-29029 May 2020 LLC Submittal of Presentation Materials Entitled ACRS Full Committee Presentation: NuScale Topic - Boron Redistribution and Associated Design and DCA Changes, PM-0620-70244, Revision 0 ML20149M1192020-05-28028 May 2020 LLC Summary of Impacts to Erai 8930 Response and Discussion on the Exemption from General Design Criterion 33 ML20141L8082020-05-20020 May 2020 LLC Submittal of Containment Response Analysis Methodology Technical Report, TR-0516-49084, Revision 3 ML20141N0122020-05-20020 May 2020 LLC Submittal of Changes to Final Safety Analysis Report, Section 6.2, Containment Systems, Section 6.3, Emergency Core Cooling System, and Technical Report TR-0516-49084, Containment Response Analysis Methodology Technical Report ML20141M7642020-05-20020 May 2020 LLC Submittal of Nuclear Steam Supply System Advanced Sensor Technical Report, TR-0316-22048, Revision 3 ML20141L7872020-05-20020 May 2020 LLC, Submittal of Second Updates to Standard Plant Design Certification Application, Revision 4 ML20141L8162020-05-20020 May 2020 LLC, Submittal of Long-Term Cooling Methodology, TR-0916-51299, Revision 3 ML20141M1142020-05-20020 May 2020 LLC Submittal of NuScale Instrument Setpoint Methodology Technical Report, TR-0616-49121, Revision 3 ML20141L8042020-05-20020 May 2020 LLC Submittal of Technical Specifications Regulatory Conformance and Development, TR-1116-52011, Revision 4 ML20128J3162020-05-18018 May 2020 OEDO-20-00167 - Response to the ACRS Letter on Combustible Gas Monitoring ML20133K0882020-05-12012 May 2020 LLC, Submittal of Presentation Materials Entitled Public Meeting Presentation: Topic - Emergency Core Cooling System (ECCS) Boron Distribution (Closed Session), PM-0420-69512, Revision 0 ML20133J9142020-05-11011 May 2020 LLC Submittal of Presentation Materials Entitled Public Meeting Presentation: Topic - Emergency Core Cooling System (ECCS) Boron Distribution, PM-0420-69511, Revision 0 ML20112F4552020-05-0101 May 2020 LLC, Design Certification Application Phases 5 and 6 Review Status ML20107F8492020-05-0101 May 2020 OEDO-2000140 - NuScale Area of Focus - Helical Tube Steam Generator Design ML20104A0792020-04-27027 April 2020 OEDO-20-00115 - Safety Evaluation Report for Topical Report TR-0516-49416, Revision 2, Non-Loss-of-Coolant Accident Analysis Methodology ML20099H0802020-04-0808 April 2020 LLC - Submittal of Presentation Materials Entitled NRC Public Meeting: Revisions to Nuscale'S EPZ Sizing Methodology Topical Report, PM-0420-69598, Revision 0 ML20098G2372020-04-0707 April 2020 Nuscale Power, LLC Submittal of Remaining Closure Items for the Emergency Core Cooling System Valve Failure Mode Effects Analysis Audit Items ML20097F1922020-04-0606 April 2020 Nuscale Power, LLC Submittal of Presentation Materials Entitled ACRS Full Committee Presentation: Nuscale Topic - Hydrogen/Oxygen Monitoring, PM-0420-69518, Revision 0 ML20094H6742020-04-0303 April 2020 LLC Submittal of Presentation Materials Entitled ACRS Full Committee Presentation NuScale Topic-Probabilistic Risk Assessment with a Focus on Emergency Core Cooling System Analysis PM-0420-69559, Revision 0 ML20092L8992020-04-0101 April 2020 LLC - Submittal of Updates to Standard Plant Design Certification Application, Revision 4 ML20072M6682020-03-30030 March 2020 Response to NuScale Letter Dated February 24, 2020, on Planned SDA Application Content ML20072H3332020-03-0909 March 2020 LLC - Submittal of Presentation Materials Entitled Public Meeting Presentation: Topic - Emergency Core Cooling System (ECCS) Boron Distribution, PM-0320-69218, Revision 0 ML20057D9002020-03-0606 March 2020 Submittal of Errata to Final SE for NuScale Power, LLC TR-1010-859-NP-A, Quality Assurance Program Description for the NuScale Power Plant ML20062F7262020-03-0505 March 2020 Request for Withholding Information from Public Disclosure for Nuscale Power, LLC Letter Public ML20069A1572020-03-0404 March 2020 LLC - Submittal of Presentation Materials Entitled ACRS Full Committee Presentation: NuScale Topical Report-Rod Ejection Accident Methodology, PM-0320-69146, Revision 0 ML20069A1772020-03-0404 March 2020 LLC - Submittal of Presentation Materials Entitled ACRS Full Committee Presentation: NuScale Topical Report-Non-Loss-of-Coolant Accident, PM-0320-69141, Revision 0 ML20069A9632020-03-0404 March 2020 LLC Submittal of Presentation Materials Entitled ACRS Full Committee Presentation: NuScale Topical Report, Loss-of-Coolant Accident Evaluation Model, PM-0320-69138, Revision 0 ML20066G2802020-03-0303 March 2020 LLC, Submittal of Presentation Materials Entitled ACRS Subcommittee Presentation: NuScale Topic - Hydrogen Monitoring, PM-0220-69071, Revision 0 ML20066G2882020-02-28028 February 2020 LLC Submittal of Presentation Materials Titled ACRS Full Committee Presentation: NuScale - Steam Generator Design (Closed Session), PM-0220-69053, Revision 0 2023-06-29
[Table view] Category:Response to Request for Additional Information (RAI)
MONTHYEARRAIO-0420-69855, LLC, Submittal of Corrected Response to NRC Request for Additional Information No. 284 (Erai No. 9225) on the NuScale Design Certification2020-04-30030 April 2020 LLC, Submittal of Corrected Response to NRC Request for Additional Information No. 284 (Erai No. 9225) on the NuScale Design Certification ML19332A1202019-11-27027 November 2019 LLC Supplemental Response to NRC Request for Additional Information No. 484 (Erai No. 8930) on the NuScale Design Certification Application ML19304B4712019-10-31031 October 2019 LLC Supplemental Response to NRC Request for Additional Information No. 466 (Erai No. 9482) on the NuScale Design Certification Application ML19296D8052019-10-23023 October 2019 LLC Response to NRC Request for Additional Information No. 526 (Erai No. 9719) on the NuScale Design Certification Application ML19283E5302019-10-10010 October 2019 LLC Supplemental Response to NRC Request for Additional Information No. 522 (Erai No. 9681) on the NuScale Design Certification Application ML19260G7352019-10-0707 October 2019 Summary of Public Meeting with NuScale to Discuss Response to RAI 9681 ML19266A5872019-09-23023 September 2019 LLC Supplemental Response to NRC Request for Additional Information No. 518 (Erai No. 9659) on the NuScale Design Certification Application ML19262G9742019-09-19019 September 2019 LLC - Submittal of Changes to Final Safety Analysis Report, Tier 1, Section 3.11, Reactor Building and Section 3.13, Control Building, and Tier 2, Section 3.8.4, Design of Category I Structure and Section 14.3, Certified ... ML19262G5762019-09-19019 September 2019 LLC - Submittal of Changes to Final Safety Analysis Report, Section 14.2, Initial Plant Test Program, Table 14.2-2, Pool Cleanup Systems Test #2, and Table 14.2-50, Module Assembly Equipment Test #50 ML19259B8102019-09-16016 September 2019 LLC Supplemental Response to NRC Request for Additional Information No. 205 (Erai No. 9044) on the NuScale Design Certification Application ML19259A0922019-09-16016 September 2019 LLC Response to NRC Request for Additional Information No. 525 (Erai No. 9705) on the NuScale Design Certification Application ML19238A3722019-08-26026 August 2019 LLC Supplemental Response to NRC Request for Additional Information No. 197 (Erai No. 9051) on the NuScale Design Certification Application ML19238A3662019-08-23023 August 2019 LLC - Response to NRC Request for Additional Information No. 523 (Erai No. 9682) on the NuScale Design Certification Application ML19215A0032019-08-0202 August 2019 LLC - Supplemental Response to NRC Request for Additional Information No. 202 (Erai No. 8911) on the NuScale Design Certification Application ML19215A0062019-08-0202 August 2019 LLC - Supplemental Response to NRC Request for Additional Information No. 441 (Erai No. 9485) on the NuScale Design Certification Application ML19212A7622019-07-31031 July 2019 LLC Response to NRC Request for Additional Information No. 523 (Erai No. 9682) on the NuScale Design Certification Application ML19212A3752019-07-31031 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 483 (Erai No. 9516) on the NuScale Design Certification Application ML19212A7992019-07-31031 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 427 (Erai No. 9408) on the NuScale Design Certification Application ML19212A6892019-07-31031 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 205 (Erai No. 9044) on the NuScale Design Certification Application ML19210D1592019-07-29029 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 401 (Erai No. 9447) on the NuScale Design Certification Application ML19210D7342019-07-29029 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 520 (Erai No. 9642) on the NuScale Design Certification Application ML19210E1462019-07-29029 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 197 (Erai No. 9051) on the NuScale Design Certification Application ML19207B3812019-07-26026 July 2019 LLC - Response to NRC Request for Additional Information No. 427 (Erai No. 9408) on the NuScale Design Certification Application ML19207A5342019-07-26026 July 2019 LLC - Response to NRC Request for Additional Information No. 523 (Erai No. 9682) on the NuScale Design Certification Application ML19207B8522019-07-25025 July 2019 LLC Response to NRC Request for Additional Information No. 194 (Erai No. 8884) on the NuScale Design Certification Application ML19203A3152019-07-22022 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 325 (Erai No. 9268) on the NuScale Design Certification Application ML19203A3212019-07-22022 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 333 (Erai No. 9282) on the NuScale Design Certification Application ML19203A3092019-07-22022 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 54 (Erai No. 8837) on the NuScale Design Certification Application ML19203A3422019-07-22022 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 154 (Erai No. 8938) on the NuScale Design Certification Application ML19200A2482019-07-19019 July 2019 LLC Response to NRC Request for Additional Information No. 522 (Erai No. 9681) on the NuScale Design Certification Application ML19200A2082019-07-19019 July 2019 LLC - Response to NRC Request for Additional Information No. 524 (Erai No. 9691) on the NuScale Design Certification Application ML19199A1172019-07-18018 July 2019 LLC - Supplemental Response to NRC Request for Additional Information No. 484 (Erai No. 8930) on the NuScale Design Certification Application ML19198A3252019-07-17017 July 2019 LLC - Supplemental Response to NRC Request for Additional Information No. 249 (Erai No. 9135) on the NuScale Design Certification Application ML19196A3682019-07-15015 July 2019 LLC Response to NRC Request for Additional Information No. 516 (Erai No. 9647) on the NuScale Design Certification Application ML19191A2202019-07-10010 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 197 (Erai No. 9051) on the NuScale Design Certification Application ML19184A6152019-07-0303 July 2019 LLC Supplemental Response to NRC Request for Additional Information No. 386 (Erai No. 9316) on the NuScale Design Certification Application ML19176A5802019-06-25025 June 2019 LLC Supplemental Response to NRC Request for Additional Information No. 232 (Erai No. 9113) on the NuScale Design Certification Application ML19170A3702019-06-19019 June 2019 LLC Supplemental Response to NRC Request for Additional Information No. 232 (Erai No. 9113) on the NuScale Design Certification Application ML19168A2442019-06-17017 June 2019 LLC - Supplemental Response to NRC Request for Additional Information No. 325 (Erai No. 9268) on the NuScale Design Certification Application ML19164A1452019-06-13013 June 2019 LLC - Submittal of Containment Response Analysis Methodology Technical Report, TR-0516 -49 08 4, Revision 1 ML19157A3262019-06-0606 June 2019 LLC - Supplemental Response to NRC Request for Additional Information No. 232 (Erai No. 9113) on the NuScale Design Certification Application ML19154A6222019-06-0303 June 2019 LLC Supplemental Response to NRC Request for Additional Information No. 202 (Erai No. 8911) on the NuScale Design Certification Application ML19154A6052019-06-0303 June 2019 LLC Response to NRC Request for Additional Information No. 514 (Erai No. 9645) on the NuScale Design Certification Application ML19151A8372019-05-31031 May 2019 LLC - Supplemental Response to NRC Request for Additional Information No. 377 (Erai No. 9380) on the NuScale Design Certification Application ML19140A4592019-05-20020 May 2019 LLC Supplemental Response to NRC Request for Additional Information No. 401 (Erai No. 9447) on the NuScale Design Certification Application ML19137A2902019-05-17017 May 2019 LLC Supplemental Response to NRC Request for Additional Information No. 156 (Erai No. 9031) on the NuScale Design Certification Application ML19137A2872019-05-15015 May 2019 LLC Response to NRC Request for Additional Information No. 519 (Erai No. 9656) on the NuScale Design Certification Application ML19126A2942019-05-0606 May 2019 LLC Supplemental Response to NRC Request for Additional Information No. 26 (Erai No. 8840) on the NuScale Design Certification Application ML19122A5092019-05-0202 May 2019 LLC - Supplemental Response to NRC Request for Additional Information No. 494 (Erai No. 9548)on the Design Certification Application ML19121A6002019-05-0101 May 2019 LLC - Supplemental Response to NRC Request for Additional Information No. 202 (Erai No. 8911) on Design Certification Application 2020-04-30
[Table view] |
Text
RAIO-0318-59249 March 22, 2018 Docket No.52-048 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738
SUBJECT:
NuScale Power, LLC Supplemental Response to NRC Request for Additional Information No. 78 (eRAI No. 8892) on the NuScale Design Certification Application
REFERENCES:
- 1. U.S. Nuclear Regulatory Commission, "Request for Additional Information No. 78 (eRAI No. 8892)," dated June 30, 2017
- 2. NuScale Power, LLC Response to NRC "Request for Additional Information No. 78 (eRAI No.8892)," dated August 22, 2017 The purpose of this letter is to provide the NuScale Power, LLC (NuScale) supplemental
response to the referenced NRC Request for Additional Information (RAI).
The Enclosure to this letter contains NuScale's supplemental response to the following RAI
Question from NRC eRAI No. 8892:
19-14 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 Darrell Gardner at 980-349-4829 or
at dgardner@nuscalepower.com.
Sincerely, Zackary W. Rad Director, Regulatory Affairs NuScale Power, LLC Distribution: Samuel Lee, NRC, OWFN-8G9A Rani Franovich, NRC, OWFN-8G9A Prosanta Chowdhury NRC, OWFN-8G9A : NuScale Supplemental Response to NRC Request for Additional Information eRAI No. 8892 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com
RAIO-0318-59249 :
NuScale Supplemental Response to NRC Request for Additional Information eRAI No. 8892 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com
Response to Request for Additional Information Docket No.52-048 eRAI No.: 8892 Date of RAI Issue: 06/30/2017 NRC Question No.: 19-14 Title 10 Code of Federal Regulations (CFR) 52.47(a)(27) states that a design certification
application must contain an final safety analysis report (FSAR) that includes description of the
design-specific probabilistic risk assessment (PRA) and its results. In accordance with the
Statement of Consideration (72 FR 49387) for the revised 10 CFR Part 52, the staff reviews the
information contained in the applicants FSAR Chapter 19, issues requests for additional
information (RAIS) and conducts audits of the complete PRA (e.g., models, analyses, data, and
codes) to obtain clarifying information as needed. The staff uses guidance contained in
Standard Review Plan (SRP) Chapter 19.0 Revision 3, Probabilistic Risk Assessment and
Severe Accident Evaluation for New Reactors. In accordance with SRP Chapter 19.0 Revision
3, the staff determines whether:
The technical adequacy of the PRA is sufficient to justify the specific results and risk insights that are used to support the [Design Certification] DC or [Combined License] COL application. Toward this end, the applicants PRA submittal should be consistent with prevailing PRA standards, guidance, and good practices as needed to support its uses and applications and as endorsed by the [Nuclear Regulatory Commission] NRC (e.g.,
[Regulatory Guide] RG 1.200).
The staff has reviewed the information in the FSAR and examined additional clarifying information from the audit of the complete PRA and determined that it needs additional information to confirm the validity of certain assumptions used in the flooding PRAs. The supporting requirements in the American Society of Mechanical Engineers / American Nuclear Society (ASME/ANS) PRA standard include provisions for documenting sources of model uncertainties and related assumptions. Please address the following questions.
- a. FSAR Table 19.1-49, Assessment of Flood Areas Containing Equipment Modeled in the Probabilistic Risk Assessment, describes the reactor building areas that include flood protection design features to protect equipment from propagating floods. Review of supporting audit information suggests that the required level of flooding protection is determined based on the assumed time available for the operator to successfully isolate the flood source. Please confirm NuScale Nonproprietary
the staffs understanding or provide an alternative explanation.
Additionally, assuming that the staff understands correctly and considering (1) the uncertainties introduced by the current level of plant design as cited in the FSAR (such as the lack of design detail on protective and mitigative features and detailed pipe routing information) and (2) the PRA should consider scenarios beyond the design basis, please explain how operators will always successfully isolate any flood sources in the reactor building.
- b. FSAR Table 19.1-48, Internal Flooding Sources, indicates the Reactor Building Spray System as a potentially significant flood source. The staff reviewed the FSAR and associated audit documentation and was unable to locate information on potential flooding scenarios associated with this flood source. Please describe the potential flooding scenarios associated with this flood source, considering as applicable, the associated potential propagation paths, equipment damage, flooding protection and mitigation features, and operator actions.
- c. FSAR Section 19.1.5.4.1 states:
An external flood could initiate a [Loss of Offsite Power] LOOP or [Loss of Direct Current] LODC because of flooding in areas containing [highly reliable DC power system] EDSS or [ 13.8 kV and switchyard system] EHVS components.
This statement implies that the EDSS and the EHVS equipment is assumed to be unprotected from floods. Please discuss why flooding protection features assumed to be available for internal flooding scenarios are assumed not to be available for external flooding scenarios.
NuScale Response:
NuScale is supplementing its response to RAI 8892 (Question 19-14) provided in letter RAIO-0817-55577, dated August 22, 2017. This supplemental response is provided in response to discussions with the NRC in a public meeting held on February 13, 2018.
This supplemental response adds an assumption to FSAR Table 19.1-54. The additional assumption is consistent with the response provided in letter RAIO-0817-55577 which stated that the PRA is based on the representative internal flooding analysis described in FSAR Section 3.4.1. To identify affected equipment, the representative analysis uses flood volumes based on the assumption that plant personnel will isolate the flood source (i.e., the flooding source does not continue indefinitely).
NuScale Nonproprietary
Impact on DCA:
Table 19.1-54 has been revised as described in the response above and as shown in the markup provided in this response.
NuScale Nonproprietary
Tier 2 NuScale Final Safety Analysis Report RAI 19-14S1 Table 19.1-54: Key Assumptions for the Internal Flooding PRA Assumption Basis Buildings that are not expected to contain flood sources or are not expected to result in a plant trip are not Engineering judgment considered.
Pipe routing and physical locations of some equipment are not defined at the design certification stage; Engineering judgment flood locations are assumed from plant drawings.
An internal flood is capable of resulting in a plant upset and transient initiating event. Engineering judgment Flooding frequencies are based on generic data for turbine and auxiliary buildings, including human- Engineering judgment induced mechanisms. A lognormal distribution is assumed.
No credit is taken for floor drains therefore, maximum flood heights are considered. Bounding assumption Operator actions to isolate a flooding event are not modeled. The time required to isolate a flood, however, Engineering judgment is used to establish the volume of water involved in the event and establish the depth of water involved in the flood.
Flooding effects for equipment located inside the containment are not considered. Equipment located in containment is designed to operate in harsh environments, including LOCAs.
Safety-related and risk significant equipment is protected from flooding effects. Although not defined at design certification, flood protection 19.1-242 (e.g., flood door, splash protection) for safety-related and risk significant equipment is a design requirement.
Equipment that is not safety-related or risk significant is exposed to flooding in the area where it is located; Bounding assumption flood-induced failure mechanisms include spray and submergence.
Passive components such as piping, tanks, heat exchangers, manual valves, check valves, relief valves, Passive equipment does not require control to operate strainers and filters are not susceptible to flood damage Electrical equipment is susceptible to flood damage which occurs instantaneously when the lowest portion Bounding assumption of the equipment is submerged. The most likely failure mechanism for flood water damage is a short-to ground, which results in an open-circuit failure mode.
If subjected to a flood, motor operated valves fail as-is and solenoid and air-operated valves fail to their de- Engineering judgment energized position.
A flood in the RXB will prevent operations from establishing makeup with the CVCS or CFDS. Bounding assumption Probabilistic Risk Assessment Consistent with the internal events analysis, high stress was considered for operator actions. Engineering judgment Equipment affected by a flood is based on the analysis summarized in Section 3.4.1. Common engineering practice Draft Revision 2