Seminars

Decision of the Scientific and Technical Council of SEC NRS of 13.06.2019

Agenda

1. Actual problems in evaluation of VVER reactor vessel radiation embrittlement and SEC NRS role in solution thereof.
2. Experience in conduct of SEC NRS safety culture self-assessment and its results.

On the first issue

Having heard the presentation of Mr. Alexander Kryukov, Doctor of Engineering Sciences and Chief Research Scientist of the Strength Division, and Mr. Ildar Akbashev, Head of Division of OKB “Gidropress”, on the actual problems in evaluation of VVER reactor vessel radiation embrittlement and SEC NRS role in solution thereof, and taken part in discussions,

STC noted that

Nowadays, one of the most important issues in evaluation of VVER reactor vessel radiation embrittlement degree is justification for extension of the burn-up life of the reactor vessel metal for 60 and more years of operation. In order to solve this problem, the SEC NRS Strength Division in cooperation with CRISM "Prometey" and OKB “Gidropress” carries out activities in the following areas:

• evaluation of the degree of radiation embrittlement of VVER reactor vessel metal, irradiated by high neutron fluencies corresponding to 60-80 years of a power unit operation;
• justification for low-temperature wet annealing of VVER reactor vessels;
• development of a method of immediate determination of brittle-fracture resistance characteristics of VVER reactor vessel metal using irradiated samples.

As a results of works performed it was revealed that

• metal of VVER-440 reactor vessels with a low content of impurity elements (cuprum, phosphorus) can be characterized as highly radiation resistant, when irradiated by neutron fluencies of ~5х1020cm-2;
• low-temperature wet annealing under the temperature of 340 ⁰С can be effective to restore the mechanical properties of the irradiated reactor vessel steels with a low content of impurity elements.

SEC NRS participation in the international project STRUMAT, the purpose of which is to evaluate VVER and PWR reactor vessels radiation embrittlement under fluencies corresponding to 60-80 years of operation, will contribute to obtaining of scientific and technical results that are necessary for justification of lifetime extension for the Russian NPP reactor vessels.

In respect to the first issue STC decided

• to approve the activity of the Strength Division in the field of evaluation of the degree of radiation embrittlement of VVER reactor vessel metals.
• to prepare a presentation on the topic “Current problems evaluation of VVER reactor vessel radiation embrittlement and SEC NRS role in solution thereof” at Session 3 of Rostechnadzor.

On the second issue

Having heard the report of Mr. Alexander Vasilishin, Head of Laboratory of Nuclear Fuel Cycle Facilities Safety Division, and Mr. Dmitriy Konoplev, Chief Specialist of Documentation Development Organization Division, on the experience in conduct of SEC NRS safety culture self-assessment and its results, and upon discussions

STC noted that

The pilot self-assessment of the safety culture was held in SEC NRS within the period from January up to May 2019. Self-assessment was performed on the basis and in compliance with the SEC NRS Order No. 16 of 31.01.2019 “On Conduct and Analysis of the Pilot Safety Culture Self-Assessment”.

1. Gremyachkin V.A., Scientific Secretary;
2. Vasilishin A.L., Head of Laboratory of Nuclear Fuel Cycle Facilities Safety Division;
3. Konoplev D.V., Chief Specialist of Documentation Development Organization Division;
4. Marulina E.S., Chief Specialist of Scientific and Managing Division.

In the process of preparation of the self-assessment the questionnaire of 168 questions was elaborated. The elaborated questionnaire considered the provisions of the Policy Statement on Safety Culture in the Field of State Safety Regulation in Atomic Energy Use (hereinafter to be referred to as Policy Statement) and OECD NEA Green Booklet (The Safety Culture of an Effective Nuclear Regulatory Body, OECD 2016, NEA No. 7247). The questionnaire makes it possible to assess all five safety culture principles specified in the Policy Statement:

• Leadership in safety related issues to be demonstrated by leaders of all levels;
• Demonstration of commitment to safety and personal responsibility of its employees and employees of the technical and scientific support organizations for high-quality implementation of the entrusted duties related to safety;
• Cooperation, transparency and information exchange with nuclear industry organizations and enterprises as well as with citizens on the issues of safety regulation in atomic energy use;
• Integrated approach to the issues of safety regulation in atomic energy use;
• Continuous enhancement of the regulatory activity, learning lessons from the own experience and activity of other state safety regulatory bodies, including foreign regulatory authorities, and self-assessment of the safety culture, encouraged at all administrational layers.

In the course of the self-assessment 65 employees of SEC NRS were questioned. Summarizing the results of the questionnaire survey the representative group submitted 60 filled-in questionnaires. 5 persons (less than 8 %) decided not to take part in the questionnaire survey. 2 questionnaires out of all submitted ones were not taken into account in the process of analysis since option «6» of the answer was ticked off for all the questions. In the process of filling in the questionnaires the respondents were suggested to make comments on the questionnaire items and process.

Upon collection and analysis of the questionnaires the report “Results of SEC NRS Safety Culture Self-Assessment”. The report analyzed good practices in safety culture, which were noted in the process of analysis of self-assessment results, and revealed some shortcomings. Moreover, the report presented proposals on implementation of the practice of safety culture self-assessment in Rostechnadzor.

In respect to the second issue STC decided that

1. To take note of the results of the pilot SEC NRS safety culture self-assessment.
2. Heads of Divisions shall submit to the Working Group the proposals on enhancement of SEC NRS safety culture based on the materials of the report DNP 4-1424/2019 “Results of SEC NRS Safety Culture Self-Assessment”. The Working Group shall develop an action plan on enhancement of SEC NRS safety culture on the basis of the received proposals (September 2, 2019).
3. The Working Group on SEC NRS Safety Culture Self-Assessment shall plan and organize a workshop on SEC NRS safety culture self-assessment in 2019 (October 17, 2019).
4. The Working Group on SEC NRS Safety Culture Self-Assessment shall prepare proposals on the conduct of a workshop in Rostechnadzor exchanging the experience in safety culture self-assessment (October 31, 2019).

STC Chairman A. Khamaza; STC Scientific Secretary V. Gremyachkin.