ML17352A576
| ML17352A576 | |
| Person / Time | |
|---|---|
| Site: | 05200045 |
| Issue date: | 01/16/2018 |
| From: | James Shea NRC/NRO/DNRL |
| To: | Joseph Colaccino NRC/NRO/DNRL |
| shea j | |
| Shared Package | |
| ML17352A635 | List: |
| References | |
| Download: ML17352A576 (8) | |
Text
January 16, 2018 MEMORANDUM TO: Joseph Colaccino, Branch Chief Licensing Branch 3 Division of New Reactor Licensing Office of New Reactors FROM: James Shea, Project Manager /RA/
Licensing Branch 3 Division of New Reactor Licensing Office of New Reactors
SUBJECT:
REGULATORY AUDIT RESULTS
SUMMARY
REPORT OF THE PROBABILISTIC RISK ASSESSMENT OF DESIGN CHANGES FOR THE ADVANCED BOILING-WATER REACTOR DESIGN CERTIFICATION RENEWAL Enclosed is the U.S. Nuclear Regulatory Commission (NRC) staffs Probablilistic Risk Assessment (PRA) Audit report regarding the GE Hitachi (GEH) Advanced Boiling-Water Reactor (ABWR) design certification (DC) renewal application (Docket No.52-045). The staff performed an off-site-audit of the process and procedures GEH used to assess proposed design changes impact on the ABWR DC PRA as part of the GEH ABWR DC renewal application.
The audit was conducted over three months, starting on July 25, 2017 and concluding with an exit meeting on September 27, 2017. The ABWR DC renewal PRA audit was completed remotely using the GEH electronic reading room (eERR). The staff reviewed several of the applicants engineering change reports and conducted phone conferences with the applicant for clarification information as part of the staff audit activities. In addition, as the audit proceeded the staff requested additional documents to review in the eRR, which were provided by GEH.
Docket No.52-045
Enclosure:
As stated cc w/encl: See next page CONTACTS: James Shea Adrian Muniz Project Manager ABWR Lead Project Manager NRO/DNRL/LB3 NRO/DNRL/LB3 (301) 415-1388 (301) 415-4093
ML17352A576 (Summary)
ML17352A635 (Pkg.) *via email NRO-002 OFFICE DNRL/LB3: PM DNRL/LB3: LA DNRL/LB3: PM DNRL/LB3: BC NRO/SPRA: BC NAME JShea SGreen AMuniz JColaccino MHayes (A)
DATE 12/16/2017 12/18/2017 12/21/2017 12/22/2017 12/21/2017 U.S. NUCLEAR REGULATORY COMMISSION REGULATORY AUDIT RESULTS
SUMMARY
OF PROBABILISTIC RISK ASSESSMENT IMPACT AS PART OF THE ADVANCED BOILING-WATER REACTOR DESIGN CERTIFICATION RENEWAL APPLICATION (Docket No.52-045)
Dates of Audit: July 27 - September 27, 2017 Audit Location: U.S. NRC Headquarters Two White Flint North 11545 Rockville Pike Rockville, MD 20852-2738 Audit Team: James Shea (NRC Project Manager)
Michelle Hayes (NRC SPRA Branch Chief (Acting))
Hanh Phan (NRC Lead Technical Reviewer)
Malcolm Patterson (NRC Technical Reviewer)
Marie Pohida (NRC Technical Reviewer)
Audit Scope The specific scope of this audit included a review of the process/guidance and all related documentation used to evaluate impact on Probablilistic Risk Assessment (PRA) of the changes resulting from the design modifications or departures as part of the GE Hitachi (GEH) Advanced Boiling-Water Reactor (ABWR) design certification (DC) renewal application.
The purpose of this audit was for the staff to (1) understand the process used to determine the potential impact of design changes or departures on ABWR design-specific PRA, (2) review related documentation and non-docketed information to evaluate conformance with the standard review plan and staff guidance, and (3) ensure the quality of the process/procedures used by GEH for PRA update meet appropriate regulatory requirements.
A list of GEH documents available for this audit is included in Table 1, List of Reports and Supporting Information for the ABWR DC Renewal PRA Audit, which was provided by the applicant during the audit.
Audit Summary During the audit entrance NRC staff made introductory remarks regarding the regulatory audit background, scope, objectives, and agenda. This included the regulatory basis for the staffs audit and the office instruction procedure for conducting a regulatory audit.
Following these remarks, GEH presented an overview of its Engineering Change Authorization /
PRA process and procedures. These processes and procedures are used by GEH to evaluate the impact of engineering changes on specific risk metrics for the ABWR.
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During the audit, the staff reviewed the documents placed in the electronic reading room (eRR).
While reviewing the process, the staff focused on three ABWR DC specific design changes as examples to better understand the details of the GEH ABWR PRA design change.
The audit concluded with an exit meeting on September 27, 2017, where the staff conveyed to GEH that the NRC had no findings in regards to the process GEH used to evaluate design changes to the ABWR in its renewal application. The staff also provided audit Observations on GEH process and procedures, during the audit exit meeting.
The audit team finds that the information presented to the staff addressed the purpose of this audit. Specifically, it provided an understanding of the technical basis, assumptions, and methods by which GEH evaluates, screens, and tracks for PRA inputs or design changes.
Detailed Review and Discussions After reviewing the documents provided in the eRR, the staff identified some design changes as having the potential to have an impact on the ABWR PRA and asked the applicant to conduct a table-top exercise with three specific change packages:
Mitigation Strategies
- Add a subsystem to residual heat removal loop B for alternating-current-independent water addition (ACIWA). The new subsystem includes a connection to the fire protection system and an external hose connection for a fire truck.
- Make the diesel-driven fire pump fuel capacity sufficient for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of operation; include severe weather/flooding protection for ACIWA and the diesel-driven fire pump.
[Remote Shutdown System] Required Changes
- During a station blackout (no offsite ac power and no combustion turbine generator or emergency diesel generator available) additional features added to the remote shutdown system panels used by the operators.
- Main control room heating, ventilation, and air conditioning is required to function following postulated aircraft impact strikes in order to support the core cooling function.
- Interface requirements are specified relevant to the loss of reactor service water and ultimate heat sink systems.
The table top exercise was conducted on September 21, 2017. The staff concluded that the process followed by GEH provides an appropriate level of evaluation for determining whether design changes could impact the ABWR PRA. Also, the audit team did not identify the need to request additional information. Notwhistanding the staffs conclusion, the staff communicated the following observations during the audits exit meeting on September 27, 2017:
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- The audit team observed that the responsible engineer assigned to an engineering change is authorized to determine that a reliability analysis is not required. It was not clear what training or qualification provides confidence that a responsible engineer will be aware of all aspects of a change that can affect the PRA.
- In the case of changes to address the aircraft impact assessment, GEH identified its potential to change the severe accident, containment, and large early release frequency assessments. These changes were not quantified for its effect on the PRA but the audit team found that the applicant evaluated them appropriately for the purpose of design certification renewal.
- During the table top exercise, the audit team noted that on some engineering change authorization (ECA) forms, the subsections referenced the PRA scope to the parent form, but the parent form did not include a clear statement regarding PRA scope. . In response, GEH initiated a condition report to evaluate the issue. Although the condition report was not yet closed at the time of the exit interview, the evaluation and its conclusions that no adverse condition exists and no action is needed were already documented.
- During the exit meeting, the staff noted that the description of the ACIWA system testing in App 19K-12 of the DCD did not include the subsystem added in CP1-ECA-0012. Because this change was not credited in the PRA, the testing of this system was considered outside the scope of the audit..
- The staff observed that the evaluation and screening process applied by GEH only considers the negative PRA impacts on core damage frequency, large release frequency, and conditional containment failure probability. Although this observation would have insignificant impact on the ABWR DC renewal application, the staff suggested that GEH should also evaluate the positive impact on its PRA to ensure that the PRA accurately reflects the as-designed, as-built, and as-operated plant.
This audit summary report supports the staff safety review that will be documented in Chapter 19 of the safety evaluation report for the renewal of the ABWR standard plant design certification.
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TABLE 1:
List of Reports and Supporting Information for the ABWR DC Renewal PRA Audit ECA Number ECA Subject CP1-1-ECA-0001 Design Changes due to Aircraft Impact Assessment CP1-ECA-0002 ABWR CST Leakage CP1-ECA-0004 ABWR DCD R5 Aircraft Impact Assessment RAI CP1-ECA-0006 ABWR DCD Revised Containment Analysis CP1-ECA-0007 ABWR DCD Rev 4 Aircraft Impact Assessment CP1-ECA-0009 ABWR DCD Gas Accumulation Locations - Addition of Vent Lines to RPV Head Spray Nozzle CP1-ECA-0010 Deletion of New Fuel Vault CP1-ECA-0012 ABWR DCD Fukushima Recommendation 4.2 - Mitigation Strategies CP1-ECA-0013 ABWR DCD COPS Size Correction CP1-ECA-0014 ABWR DCD Fukushima Recommendation 4.2 - Mitigation Strategies - FLEX CP1-ECA-0015 ABWR DCD Fukushima Recommendations 4.2 - Electrical Strategies CP1-ECA-0016 ABWR DCD Spent Fuel Pool Wide Range Level Instrumentation CP1-ECA-0017 ABWR DCD Aircraft Impact Assessment - Civil CP1-ECA-0018 ABWR DCD Aircraft Impact Assessment - Mechanical CP1-ECA-0019 ECCS PCT DCD Update CP1-ECA-0020 ABWR Tornado and Hurricane Missile Speeds CP1-ECA-0021 ABWR Mitigation of Open Phase Condition (OPC)
CP1-ECA-0022 RAI 09.05.01-1 concerning Multiple spurious operations (MSOs)
CP1-ECA-0023 ABWR ECCS Suction Strainer Design Change- GE Optimized Stacked Disk Page 1
TABLE 1:
List of Reports and Supporting Information for the ABWR DC Renewal PRA Audit Procedure # Title CP-03-113 Engineering Change Control WI-03-113-01 NPE Design Change Control WI-03-113-04 Product Design Change Control Evaluation of Changes Affecting NRC Design Certification Documents WI-03-113-05 GEH Product Design Change Control - PRA Model Maintenance and Update Additional Documents added to the EFF during the Audit WI-03-113-04-F01 Form associated with WI-03-113-04 CP-03-113-F01 Form associated with CP-03-113 (Engineering Change Authorization)
CP-03-113-F02 Form associated with CP-03-113 (Engineering Change Authorization)
CP-03-100-G230, Reliability Analysis CP-03-100-G515 PLM Issue Management ISS-0000617 for ECAs 12 and 14 - PROPRIETARY ISS-0000745 for ECA 18 - PROPRIETARY CR-26820 for PRA Scope Pointer Error in ECAs - PROPRIETARY CR-26862 for Error in DCD Section 19.K.5 (4) - PROPRIETARY Page 2
TABLE 2:
ABWR DC Renewal PRA Audit July 27 through September 27, 2017, GEH Participants Last name First Name Organization Title Schumitsch Walter (Skip) GEH Project Management Overall GEH Lead Enfinger Timothy GEH Senior Licensing Engineer Regulatory Affairs GEH Lead Campbell Patricia GEH Reg Affairs Audit Support Beard Alan GEH Principal Engineer Hinds David GEH Technical Leader Seeman Glen GEH Senior PRA Engineer Li Jonathan GEH PRA Technical Lead Miller Gary GEH Manager, Risk and Reliability Marshall AnnMarie GEH Senior Engineer, Configuration Management Head Jerry GEH Senior Vice President, Regulatory Affairs