ML20357B112
| ML20357B112 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 12/22/2020 |
| From: | Mark King NRC/NRR/VPOB |
| To: | - No Known Affiliation |
| Garry Armstrong | |
| References | |
| Download: ML20357B112 (3) | |
Text
Greene, Delores
Subject:
ACTION: Process Email to Daniel Shea from Mike King into ADAMS (FW: Letter to Chairman, NRC, on Vogtle 3&4 Human Factors Engineering and Pressurizer Importance: High From: King, Mike Sent: Tuesday, December 22, 2020 2:51 PM To: djs7500@aol.com <djs7500@aol.com>
Subject:
RE: Letter to Chairman, NRC, on Vogtle 3&4 Human Factors Engineering and Pressurizer
Dear Mr. Shea:
I am the Director of the Vogtle Project Office within the U.S. Nuclear Regulatory Commissions (NRC) Office of Nuclear Reactor Regulation. I appreciate your concerns and share your goal of a safe nuclear industry. I am responding to your November 25, 2020, email to Chairman Svinicki, that included an attached letter dated October 3, 2017, regarding your concerns related to the Vogtle Electric Generating Plant (VEGP), Units 3 and 4.
We believe that your concerns fall into two broad categories: (1) an apparent disconnect between operator training design and Human Factors Engineering (HFE) and the associated implications for real time task overload; and (2) the AP1000 pressurizer volume and implications for the safety of the current operating fleet given lessons from the Three Mile Island, Unit 2 (TMI2) accident.
Regarding HFE training and human performance, the staff has reviewed your concerns and believe that the issues you raised have been addressed. The NRC uses NUREG0711, Human Factors Engineering Program Review Model, Revision 2 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML040770540) to review Human Factors programs. NRC staff developed NUREG0711, Revision 2, in coordination with Brookhaven National Laboratory. The staff considered Revision 2 when approving the AP1000 Design Certification (DC) and the VEGP, Units 3 and 4, Combined License (COL) application (see Section 13.2, Training, Section 18.6, Staffing and Qualifications, and Section 18.10, Training Program Development, of the VEGP COL final safety evaluation report (SER) (ADAMS Accession No. ML12271A048) and Chapter 18 of the AP1000 Design Certification Document final SER (ADAMS Accession No. ML112061231)).
NUREG0711 says, in part, that the licensee or applicant must use a Task Analysis (TA). TA is a very broad term including several different acceptable methods. The job task analysis (JTA) developed by the Institute of Nuclear Power Operations (INPO) is just one TA method that has a long history within the nuclear industry. The TA is one of 12 elements of a comprehensive human factors program, all of which were found to be acceptable during the AP1000 DC and VEGP, Units 3 and 4, COL review. Portions of the program are confirmed as needed by inspections, tests, analyses, and acceptance criteria (ITAAC) and NRC inspections.
Human Factors programs which are consistent with NUREG0711 include numerous controls to ensure that both engineering insights as well as the perspectives of operators are included in the design process. These insights are then considered when developing training programs by the COL holder. For instance, accident 1
analyses and probabilistic risk assessment (PRA) insights are used to identify important human actions as part of a human factors program (see Section 18.6 of NUREG0711). Figure 7.1, The role of human reliability analysis in the HFE program, of NUREG0711, Revision 2, illustrates how important human actions are used to inform the design of the plant, plant procedures, and operator training program. In addition, performance based testing (illustrated in Figure 7.1 as the Human Factors Verification and Validation box) provides confidence that elements of the training program and the design work to support safe and reliable operation.
The staff inspected Southern Nuclear Companys Human Factors Verification and Validation program, which included an assessment of operator workload, and determined that the licensee followed the appropriate procedures and produced adequate results (ADAMS Accession No. ML16336A244).
The NRC approved a Knowledge and Abilities (K/A) catalog (NUREG2103, Knowledge and Abilities Catalog for Nuclear Power Plant Operators: PressurizedWater Reactors, Westinghouse AP1000 (ADAMS Accession No. ML11307A367)) that was developed using insights from subject matter experts (e.g., system engineers and operators) who identified the K/A necessary to operate the plant. Licensed operators must have knowledge of plant systems and plant responses. The NRC approves the written examination, administers the operating tests for the initial licensing of operators, and conducts routine oversight of proficiency training and examinations for licensed operators to provide confidence that the operators do in fact have the K/A needed to safely operate the plant (ADAMS Accession Nos. ML15212A744 and ML20127H986). Since training is a critical component to safety, the NRC requires that all licensed operator training programs be derived from a systems approach to training as defined in Title 10 of the Code of Federal Regulations (10 CFR) 55.4.
Finally, the staff appreciates the opportunity to respond to your concerns regarding why the Westinghouse AP1000 pressurizer is 40 percent larger than comparably sized existing nuclear units and if this was necessary in light of the TMI2 accident. The Westinghouse AP1000 pressurizer size was designed as explained in the documents you referenced. This increased volume provides plant operating flexibility and minimizes challenges to the safety relief valves. The AP1000 Design Control Document describes the use of the pressurizer as well as the ability of the plant to handle load rejects and to perform load following. The design features chosen for the AP1000 included a larger pressurizer to allow for meeting the AP1000 Chapter 15 safety analysis as well as operational considerations, such as load following.
The AP1000 design and safety related systems are significantly different than currently operating fleet safety related systems. As a result, the AP1000 Chapter 15 safety analysis is also significantly different than the currently operating fleet. These designs have all been approved by the NRC. The current nuclear fleet have pressurizers that have been designed, analyzed, and approved by the NRC to meet their Updated Final Safety Analysis Report (UFSAR) Chapter 15 safety analyses. Therefore, the NRC does not have a safety concern about the size of the pressurizers of the current fleet with respect to either their accident analyses or their ability to perform their function. The staff has determined that based on their designs, both the current fleet and the new AP1000 pressurizer design and associated accident analyses are acceptable and safe.
With regard to the relationship that you drew between the AP1000 design and the accident at TMI2 in 1979, among the many actions NRC has taken to address the accident, 10 CFR 50.34 was added to the Code of Federal Regulations. 10 CFR 50.34(f)(2)(iii) requires COL applicants to demonstrate that they applied stateof theart human factors principles to the main control room design of reactors. NRC staff uses Chapter 18 of NUREG0800 Standard Review Plan to evaluate an applicants human factors program. Chapter 18 includes a reference to NUREG0711 which contains the 12 elements of such a program and includes acceptance criteria which outline an acceptable human factors program.
On behalf of the NRC, I thank you for your concerns, and hope that we have addressed them.
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Sincerely, Mike King Director, Vogtle Project Office Office of Nuclear Reactor Regulation US Nuclear Regulatory Commission 3014156637 One White Flint North (O13H19) 3