ML19057A209

U.S. Nuclear Regulatory Commission (NRC) Experience: Oversight of the First Two Integrated System Validation Tests of New Reactor Control Rooms

ML19057A209
Person / Time
Issue date:	02/26/2019
From:	Brian Green NRC/NRR/DIRS/IRAB
To:
Green B, NRR/DIRS, 301-415-6728
References
Download: ML19057A209 (5)

Text

U.S. Nuclear Regulatory Commission (NRC)

Experience: Oversight of the First Two Integrated System Validation Tests of New Reactor Control Rooms Office of Nuclear Reactor Regulation What Is Integrated System Validation?

Integrated system validation (ISV) is an important part of human factors verification and validation activities as described in NUREG-0711. ISV is performed to provide performance-based evidence that the integrated system design can safely be used to operate the plant. This includes using a variety of performance measures to assess how well the operators interact with the hardware, software, and procedures in the main control room.

Human engineering discrepancies (HEDs) are identified if performance criteria are not met. HEDs are analyzed and tracked to ensure that any HEDs that could impede safe operation are addressed with changes to the design, procedures, or operator training before operation.

Recent NRC Experience ISV testing can be particularly complex, requiring a sophisticated testbed and test participants who are trained to a level roughly equivalent to a licensed operator. The NRC considers these and other factors when adjusting its oversight to balance the need for adequate validation while considering the associated costs.

The NRC recently conducted a series of inspections of the AP1000 ISV and a series of audits of the NuScale ISV. These were the first implementations of Inspection Procedure (IP) 65001.23. In addition, the staff used IP 43002 when conducting vendor inspections.

This presentation summarizes NRC experience with oversight of the ISV process.

Key ISV Criteria from NUREG-0711 Conditions Realistic and challenging operating scenarios Wide variety of operational conditions (normal operations, design-basis accidents, startup, etc.)

Realistic secondary tasks Performance Measures Objective measures (time, accuracy, errors, etc.)

Subjective measures (workload, situation awareness, etc.)

Plant Personnel Representative of people who will one day operate the plant Training and qualifications Data Analysis Variety of analyses used to draw conclusions about the safe operation of the plant and to identify issues that must be resolved in order to assure safe operation Validation Personnel Independence from the design team Specially qualified for conducting ISV Test Design Scenario sequencing Test procedures Test personnel training Participant training Pilot testing Validation Testbed High-fidelity simulator (usually the same one used for operator licensing)

Recent NRC Experience with ISV The NRC reviewed and approved the ISV implementation plan.

Vendor inspections were used to ensure ISV was conducted in accordance with the implementation plan and to review ISV analyses and conclusions.

LICENSING APPROACHES WITH AND WITHOUT DESIGN ACCEPTANCE CRITERIA LEAD TO DIFFERENCES IN OVERSIGHT The Commission allows the use of design acceptance criteria (DAC) for licensing the human factors aspects of main control room (MCR) designs. When DAC are used, inspections, tests, analyses, and acceptance criteria are used to verify completion of the DAC.

Alternatively, applicants may choose to complete the control room design before design certification and not use DAC. This can lead to alternate strategies for the timing and conduct of the ISV. As such, the NRC has taken different approaches to overseeing the ISV process.

AP1000: Used the DAC approach by submitting implementation plans that the staff reviewed and approved during the design certification review.

NuScale: Did not use DAC as other applicants have done in the past.

Instead, NuScale had a nearly complete MCR design when it submitted the design certification application. ISV is being conducted concurrently with the design certification review.

The NRC reviewed and commented on the ISV implementation plan.

An audit of the ISV test was used to ensure that it was conducted in accordance with NUREG-0711.

An audit will be used to review the ISV results and analyses concurrent with the Phase 4 safety evaluation.

AP1000 (with DAC)

NuScale (without DAC)

Key Points of Interest during Inspections/Audits Planning

• Implementation plan should be consistent with NUREG-0711

• Principles described in NUREG-0711 are used to ensure credible ISV results

• Applicants should discuss the timing of the ISV during preapplication interactions Execution

• ISV should be conducted consistent with an NRC-approved implementation plan or NUREG-0711 if a results summary report is submitted in lieu of an implementation plan Analyses

• Review the conclusions drawn about pass/fail criteria and diagnostic analyses

• Confirm appropriate identification and prioritization of HEDs

• Determine whether design changes are needed Retesting

• Determine whether design changes warrant retestingis the change likely to invalidate conclusions drawn by the ISV?

• Verify that appropriate retesting methods were used

• Verify that design changes cause no new human performance issues

Contact Information U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation 11555 Rockville Pike Rockville, MD 20852 Brian.Green@nrc.gov www.nrc.gov References NRC Guidance Documents NUREG-0711, Revision 3, Human Factors Engineering Program Review Model, November 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12324A013)

IP 65001.23, Inspection of Human Factors Engineering Verification and Validation ITAAC, December 22, 2014 (ADAMS Accession No. ML14279A071)

IP43002, Routine Inspections of Nuclear Vendors, July 15, 2013 (ADAMS Accession No. ML13148A361)

AP1000 Inspection Reports NRC Inspection of Westinghouse Electric Company Report No. 99900404/2015-201, April 5, 2016 (ADAMS Accession No. ML16091A462)

NRC Inspection of Westinghouse Electric Company Report No. 99900404/2016-206, December 9, 2016 (ADAMS Accession No. ML16336A244)

NRC Inspection of Westinghouse Electric Company Report No. 99900404/2017-202, July 30, 2018 (ADAMS Accession No. ML18207A243)

NuScale Audit Reports July 25, 2017-February 14, 2018, NuScale Human Factors Engineering (HFE) Audit Report (ADAMS Accession No. ML18135A049)

June 26-28, 2018, NuScale HFE Audit Summary Report (ADAMS Accession No. ML18208A370)

July-August 2018, NuScale ISV Audit Summary Report (ADAMS Accession No. ML18298A190)