Support to SNRIU in activities related to NPP safe operations of risk-informed approaches (operation and maintenance).

Component A (UK/TS/41) – Development and implementation of risk-informed approaches to NPP operation and maintenance

The introduction of risk-informed approaches at nuclear power plants requires systematic development and implementation of appropriate methodologies to perform safety assessments and to make regulatory decisions related to NPP submittals. When considering the Ukrainian operating organisation activity on the introduction and use of risk-informed approaches in the operation of its NPP units, including maintenance and equipment in-service inspection practices, the need for providing technical support to SNRIU to improve its assessment methodology and regulatory requirements related to risk-informed approaches was identified. The UK/TS/41 project was launched to provide this support to the Ukrainian nuclear regulatory body (SNRIU) in risk informed decision making and in utilization of PSA methods in regulatory work.

Component B (UK/TS/42) – Development of the integrated NPP safety oversight system

The NPP safety indicators system is a tool used to assess the operation safety level of the NPP as part of the regulatory supervision process. A number of countries developed and implemented specific safety indicators systems and EU regulatory authorities achieved considerable progress in this area.

Ukraine also started to implement a system for assessing the operational safety level and technical state of the Ukrainian NPPs. From 2009 on, the Ukrainian NPP operating organisation (NAEK "Energoatom") developed and adopted a guideline specifying the list of safety indicators and the methodology for their calculation and analysis. The guide also appropriated the preparation of relevant reports and their submittal to SNRIU. Presently the operating organisation is testing the proposed system of safety indicators to assess the operational safety level and technical state of the Ukrainian NPPs.

In order to improve the existing Ukrainian safety oversight system and to be able to use the information on the NPPs’ safety state as much as possible, it was proposed to develop and implement an integrated NPP safety oversight system. The UK/TS/42 project was launched to provide the necessary support to SNRIU during the design, development, implementation and testing of the integrated NPP safety oversight system.

The integrated oversight system uses the safety indicators of the NPP for planning specific regulatory activities. The system integrates the monitoring of NPP safety level with the use of NPP safety indicators and the regulatory oversight to focus the inspections on those items that potentially have the highest impact on plant safety.

Component C (UK/TS/43) – Assessing the operating organisation materials on severe accident analysis and management

At present SNRIU complies with IAEA standards and WENRA requirements on the scope of safety substantiation for NPPs and their probabilistic and deterministic safety analysis. Up to now, the operating organisation has completed pilot research projects for Level 1 and 2 Probabilistic Safety Analysis, analysis of design-basis accidents and beyond design-basis accidents, except severe accidents. The next stage needed is to extend the scope of safety substantiation to perform the analysis of severe accidents and to develop guidelines on their mitigation and management. The importance of the severe accidents analysis was confirmed by experts within the IAEA missions on design safety carried out in the framework of the "Memorandum on Mutual Understanding of Energy Cooperation between the European Union and Ukraine in the field of nuclear safety".
In order to meet the requirements of SNRIU, the Ukrainian operating organisation has developed a comprehensive program on severe accident analysis. This program outlines the scope of severe accident analysis and the procedure for the development of severe accident management guidelines (SAMGs). To be able to assess this activity and to inspect the documents to be developed by the operating organisation, SNRIU needs to have access to up-to-date methodologies and international experience in assessing design and operational documentation on severe accident analysis and management. The UK/TS/43 project was launched to provide the necessary support to SNRIU during the review of severe accident analyses and SAMGs prepared for the Ukrainian NPPs by the operating organisation.

Component D (UK/TS/44) – Regulatory issues about reactor pressure vessel operations

According to the Ukrainian requirements of "General provisions of NPP safety" the operating organisation periodically has to perform a re-assessment of the safety of its NPP units. This re-assessment is conducted to take into account aging effects, modernisation measures, operational experience, changes in regulatory requirements, etc., in order to fully confirm the capability of the NPP units for further safe operation. During the safety re-assessment of NPP units, special attention is paid to the assessment of the state and residual lifetime of critical (i.e. non-replaceable) components. One of the most important non-replaceable components is the reactor pressure vessel (RPV). Justification of the safe operation of the RPV is imperative for ensuring the safe NPP operation. SNRIU considers the general requirements for NPP safe operation and periodical safety re-assessment satisfied, when the whole safe operation process of NPP systems and components, and particularly, the safe operation of the reactor pressure vessel are justified satisfactorily.
Currently, several essential technical aspects are insufficiently regulated in the Ukrainian national rules and standards. The regulatory documents in force in Ukraine were developed more than 20 years ago and presently they do not fully consider the contemporary level of science and technology, as well as operational experience.
The UK/TS/44 project was launched to provide the necessary support to SNRIU to take into account the experience of the EU countries which have thoroughly developed regulatory norms and standards in this field.

Component A (UK/TS/41) – Development and implementation of risk-informed approaches to NPP operation and maintenance

The main objectives of the project were as follows:

• Strengthening SNRIU's capabilities in the use of risk-informed approaches and probabilistic methodologies in its activities and developing SNRIU's ability to conduct comprehensive expert assessments of related operating organisation documents.
• Exchanging experience and harmonization of approaches to develop and use methods such as
  • Risk-informed in-service inspection (RI-ISI);
  • Maintenance optimization using risk assessment methods;
  • Optimization of technical specifications;
  • Justification of NPP changes;
  • Safety analysis of safety up-grade measures;
  • Living PSA.
• Advising SNRIU how to review and assess the operators’ activities in this field and providing advice on relevant regulations.

The assistance work was performed by a consortium led by RISKAUDIT with the following members: TÜV-Süd (Germany), ITER-Consult (Italy), STUK (Finland) and SSTC (Ukraine). Results
The project consisted of two technical tasks as follows:

Task 1 – Reviews (technical assessments) of the operating organisation materials

This task performed document reviews related to the use of risk-informed approaches in operation, maintenance and in-service inspection at the Ukrainian NPPs. The task was divided into two subtasks, dealing with maintenance related and operations related reviews, respectively.

Task 2 – Improvement of regulations

Task 2 carried out the comprehensive analysis of the existing Ukrainian legislation to enable a full use of risk-informed approach at the Ukrainian NPPs. It also improved existing draft regulations and helped to develop final drafts of regulatory and legal documents on using risk-informed approaches in NPP operation and maintenance. It also provided recommendations to regulate the implementation of RI-ISI in general and on the use of RI-ISI for plant piping in particular.

The final meeting of UK/TS/41 was held on the 6th of November, 2015, in Brussels, Belgium. According to the evaluation approved at the final meeting, the final completion status of the two project tasks were as follows:

• The goals of Task 1 were only partially achieved, due to the fact that the Khmelnitsky NPP guides on risk-informed maintenance programs and activities were delayed and their review could not be performed before project closure. It is expected that these documents will be submitted for review during 2016. In order to finish the remaining reviews the continuation of the technical work is planned in the framework of the on-going UK/TS/50 project.
• The goals of Task 2 were fully achieved and the task was completed successfully. The draft regulations prepared in Task 2 will be used by SNRIU in the framework of "Plan for Regulations Development".

In other aspects, the project work programme was performed as planned and the results and deliverables were according to the original objectives. The work carried out in the project helped to strengthen the capabilities of SNRIU to be able to use of risk-informed approaches and probabilistic methodologies in its activities. It also contributed to the development of SNRIU's ability to conduct comprehensive expert assessment of related operating organisation materials.

The project provided several reviews of regulations and other documents related to risk-informed approaches to NPP operation and maintenance. These reviews were jointly carried out by the European experts and experts from SSTC, the technical support organisation of SNRIU.

Component B (UK/TS/42) – Development of the integrated NPP safety oversight system

The main objective of the project was to strengthen SNRIU's capabilities in the use of risk-informed approaches and probabilistic methodologies. This goal was achieved by developing an integrated NPP safety oversight system, based on the use of NPP safety indicators and risk-informed inspections focusing on aspects that have the greatest potential impact on NPP safety. The project also promoted the harmonization of safety regulation practice in Ukraine with the practice of EU countries. Specific project objectives were as follows:

• Promoting, introducing and strengthening modern regulatory practices in Ukraine, especially the risk-informed approach in selected regulatory areas.
• Strengthening SNRIU's capabilities in regulatory decision-making with the use of risk assessment methods;
• Transferring state-of-art knowledge and experience in risk-informed regulatory methodologies and practices;
• Upgrading nuclear safety regulations in force in Ukraine, with respect to risk-informed methods and practices.

The assistance work was performed by a consortium led by RISKAUDIT with the following members: ASN (France), GRS (Germany), IRSN (France) and SUJB (Czech Republic).

Component C (UK/TS/43) – Assessing the operating organisation materials on severe accident analysis and management

The basic objective of the project was to promote, introduce and strengthen modern regulatory practices in Ukraine, especially in the assessment of severe accident analysis and severe accident management guidelines. Specific project objectives were as follows:

• Improving and formulating the Ukrainian regulatory requirements on severe accidents analysis and management;
• Providing SNRIU with an up-to-date methodology to assess operating organisation activities on severe accident analyses and severe accident management guidelines development and implementation;
• Provision of training to SNRIU staff on the related subjects;
• Developing the necessary internal review procedures;
• Strengthening the capabilities of SNRIU to be able to assess the documents on SA analysis and SA management developed by the operating organisation.

The assistance work was performed by a consortium led by RISKAUDIT with the following members: GRS (Germany), IRSN (France), STUK and VTT (Finland), and SSTC (Ukraine).

Component D (UK/TS/44) – Regulatory issues about reactor pressure vessel operations

The basic objective of the project was to provide support to SNRIU in the regulatory process applied for periodic safety re-assessment of Ukrainian NPPs, especially in issues related to reactor pressure vessel operations. Specific project activities were as follows:

• Joint analysis of available Ukrainian experience in the framework of licensing required for reactor pressure vessel (RPV) safety re-assessment.
• Organisation of a workshop to discuss the methodology for the assessment of factors impacting RPV operation (e.g. neutron embrittlement, brittle fracture and fatigue).
• Formulation of recommendations for the review of documentation prepared to assess the residual lifetime for safe operation of the RPV and on the improvement of the current regulations.

The assistance work was performed by a consortium led by RISKAUDIT with the following members: GRS (Germany), ITER-Consult (Italy), STUK and VTT (Finland), SUJB (Czech Republic) and SSTC (Ukraine).

The project consisted of four technical tasks as follows:

Task 1 – Concept of the integrated oversight system

Task 1 prepared the basic concept for the development of an Integrated Oversight System (IOS). The concept defined provisions on NPP safety indicators, inspections based on safety indicator data and risk assessment results, as well as significance assessment of the detected safety issues. The first part of the task included a training course focusing on the transfer of knowledge, methodologies and best European practice related to risk-informed decision making and in particular to integrated oversight systems. The second part was devoted to the development of a draft guide describing the development process for the creation of an integrated safety oversight system for Ukraine.

Task 2 – NPP safety indicators system

Task 2 dealt with the development of the safety indicators system as a tool to be used by SNRIU. The list of proposed NPP safety indicators was prepared, together with the methodology for their calculation, analysis and application. The task included a training course providing information on methodologies and best European practice regarding safety indicators. In the next phase technical support was provided to SNRIU during the actual development of the NPP safety indicators.

Task 3 – Procedure for planning inspections

Task 3 developed the procedure for planning inspections to be performed in the framework of the IOS. Several aspects were covered in a workshop, including human resources, inspection planning and preparations, documentation processing and evaluation of inspections in Europe and Ukraine. Examples were provided for developing inspection planning procedures. A draft procedure for the preparation of basic inspection programme was also presented together with a draft basic inspection programme. Inspection procedures provided by the Beneficiary were also analysed. Draft procedures to prepare the annual inspection plans and final draft procedures on performing risk informed inspections were also developed and presented.

Task 4 – Implementation of the integrated oversight system

Task 4 developed a pilot application of the integrated oversight system. The IOS was based on the concept defined by Task 1 and on the results of Tasks 2 and 3. The safety indicators were calculated, safety problems and issues were assessed and analysed, and risk-informed inspections were carried out for selected VVER-1000 NPP units. One subtask was devoted to the improvement of corresponding Ukrainian regulations. The Ukrainian regulatory and legal framework was reviewed thoroughly and recommendations to improve the legal context introducing the integrated NPP safety oversight system were formulated. Assistance was also provided to develop the corresponding draft regulatory documents.

The final meeting of UK/TS/42 was held on the 5th of November, 2015, in Brussels, Belgium. The final meeting concluded that the project work programme had been performed as planned and all results and deliverables were according to the original objectives.

The work carried out in the project helped the Beneficiary to strengthen SNRIU's capabilities in the use of risk-informed approaches and probabilistic methodologies in its activities. This goal was achieved by developing an integrated NPP safety oversight system, based on selected NPP safety indicators and risk-informed inspections. The project contributed to the harmonization of the safety regulation practice in Ukraine with that of in the EU countries. During project execution an effective knowledge- and methodology transfer took place between EU and Ukrainian experts.

Component C (UK/TS/43) – Assessing the operating organisation materials on severe accident analysis and management

The project consisted of three technical tasks as follows:

• Task 1 – Improvement of the regulatory requirements on severe accidents analysis and management based on IAEA, WENRA standards and good Western practice

Task 1 concentrated on the improvement of Ukrainian regulatory requirements on severe accident analysis and management. Task 1 included the following activities:

1.1 - Presentation of European experience and practices

This sub-task dealt with transfer of knowledge, methodologies and best European practices related to SA analysis and management.

1.2 - Improvement of existing regulations

This sub-task included reviews of existing SNRIU documentation containing requirements for severe accident analysis and management. Recommendations were also developed to revise these documents.

1.3 - Improvement of existing procedures for assessing the documentation on analysis and management of severe accidents

Using the recommendations formulated in sub-task 1.2, the local TSO prepared a draft of the new regulatory document (SA regulations on SA / SAMG review methodology). EU experts reviewed the draft and based on their recommendations SSTC finalized the document.

• Task 2 – Expert support

Task 2 dealt with the technical review of the following documents: documents on severe accident analysis; guidelines on severe accident management; technical and analytical substantiations of safety improvement measures aimed at preventing severe accidents. Task 2 included the following activities:

2.1 – Documents on severe accident analysis

This sub-task provided technical support to SNRIU during the assessment of documents on severe accident analysis, including relevant parts of the Safety Analysis Report for the pilot Zaporizhzhya NPP Unit 1 (VVER-1000/320). The documents assessed contained analytical justifications for SAM strategies at nominal power and at shutdown plant states, including the Spent Fuel Pool (SFP).

2.2 – Guidelines on severe accident management

This sub-task provided technical support to SNRIU during the assessment of SAMGs. The documents assessed were produced by two industrial on-site assistance projects (U1.05.07 T1 and T2, Zaporizhzhya NPP Unit 1) and they contained SAMGs at nominal power and at shutdown modes (including SFP).

2.3 – Technical and analytical substantiations of safety improvement measures

This sub-task provided technical support to SNRIU during the assessment of various technical and analytical substantiations of safety improvement measures aimed at preventing severe accidents and reducing consequences of severe accident progression for the Zaporizhzhya NPP Unit 1.

• Task 3 – Training of experts

Task 3 was aimed to improve the competence of SNRIU in safety assessment and licensing by providing theoretical and practical training. As a result of this training SNRIU and its TSO are able to perform independent safety assessment of complete SAMG documentation and to review the SAR parts dealing with severe accidents. Task 3 included the following work:

3.1 – Theoretical training course

The sub-task provided training to the Ukrainian experts on the theoretical basis of severe accident analysis and management. It also included training to perform regulatory review of documents on severe accident analysis and SAMGs.

3.2 – Practical training course

The sub-task provided training to the Ukrainian experts on methods to verify calculations and to analyse individual accident phenomena and SAM strategies.
The final meeting of UK/TS/43 was held on the 4th of November, 2015, in Brussels, Belgium.

According to the evaluation approved at the final meeting, the project was concluded successfully and all tasks were carried out as defined in the Terms of Reference document. The Beneficiary emphasized the excellent communication within the project and that results were presented at two international conferences (ERMSAR 2015 and Eurosafe 2015).

The final meeting also concluded that the project work programme had been performed as planned and all results and deliverables were according to the original objectives.

The work carried out in the project helped the Beneficiary to promote, introduce and strengthen modern regulatory practices in Ukraine in the field of severe accident analysis and severe accident management guidelines. It also strengthened and extended the capabilities of SNRIU and its TSO in the related technical fields. During the execution of the project a very effective knowledge- and methodology transfer took place between the EU and Ukrainian experts.

Component D (UK/TS/44) – Regulatory issues about reactor pressure vessel operations

The project consisted of two technical tasks as follows:

• Task 1: Analysis of the current regulatory framework establishing the regulatory requirements for assessing substantiation of RPV safe operation with respect to brittle fracture and developing recommendations on its improvement.

Task 1 dealt with the assessment and revision of selected SNRIU documents related to the periodic safety re-assessment of Ukrainian NPPs. EU and Ukrainian experts jointly assessed existing SNRIU documents establishing regulatory requirements for assessing substantiation of RPV safe operation with respect to brittle fracture. Recommendations were developed to amend these documents, the recommendations focused on improving those regulations that establish regulatory requirements for assessing substantiation of RPV safe operation under brittle fracture analyses in modes that result in thermal shock. The final aim was to harmonize the Ukrainian regulatory practice with the regulations of the EU countries.

• Task 2: Assessing the substantiation of safe operation of reactor pressure vessels under the periodic safety reassessment.

During the preparatory phase of the project it was clearly identified that Ukrainian national regulations and guidelines related to RPV calculations need to be improved. In particular, it was necessary to revise the national "Methodology for strength and lifetime assessment of VVER reactor pressure vessels during operation", and to identify a unified approach to calculations applied to justify operational safety of RPVs. It was also decided that for this purpose, the operating organisation was going to develop a "Standard program for technical state-assessment and long-term operation of VVER reactor pressure vessels". The Standard Program was to include a new revision of national methodology, a RPV ageing management program, etc. Task 2 was therefore devoted to the review of the Standard Program and to the creation of an appropriate methodological basis of activities relevant to the safe operation of RPVs.

The scope of Task 2 was modified twice during the course of the work. This caused some delays but the basic reason for the delay was the fact that the Standard Program for performing the periodic safety reviews at Ukrainian NPPs was not submitted in time. Task 2 was only partially finished and the review of the Standard Program – due to be ready in 2016 – could not be carried out within the time frame of the project. However, the related methodological document (Methodology for technical assessment of the Standard Program) was prepared and approved by the Beneficiary.

The final meeting of UK/TS/44 was held on the 24th of November, 2015, in Kiev, Ukraine. According to the evaluation at the final meeting, the project was concluded successfully, except some sub-tasks that could not be completed due to document submission delays. The "Standard program for technical state assessment and long-term operation of VVER-1000 reactor pressure vessels" (to be prepared by the operating organisation) will be reviewed in the framework of the on-going UK/TS/50 project.
The work carried out in the project helped the Beneficiary to strengthen the capabilities of SNRIU in the safety re-assessment of the Ukrainian NPP units based on the review of safety analysis of RPV safe operation. It also extended the capabilities of SNRIU and its TSO in the related technical fields. During project execution very effective knowledge- and methodology transfer took place between the EU and Ukrainian experts.