STATE NUCLEAR REGULATORY INSPECTORATE OF
20 November 2012 Kyiv No. 15
On safety criteria and requirements
for construction of new NPP units
in the light of the
The Fukushima-1 accident became the starting point for safety reassessment of operating NPPs and substantial enhancement of safety requirements for NPPs under design and construction. The IAEA started revision of safety standards under the Action Plan on Nuclear Safety approved by the IAEA General Conference in September 2011. The Western European Nuclear Regulators’ Association (WENRA) issued the document Safety of New NPP Designs for public discussion.
In compliance with Presidential Decree No. 585/2011 dated 12 May 2011 "On Resolution of the National Security and Defense Council of 8 April 2011 On Improvement of Operational Safety of Ukrainian Nuclear Power Plants", the SNRIU thoroughly revises regulations and standards on nuclear and radiation safety. However, new regulations will not be implemented until
Hence, taking into account the Law of Ukraine On Siting, Design and Construction of Units 3 and 4 of the
The presentation of the Nizhny Novgorod Public Corporation Engineering Company Atomenergoproject (
The following conceptual key requirements have been identified under the efforts undertaken by the
1. Revision of approaches to severe accident management. Revision and identification of acceptance criteria.
The designs of new NPPs should demonstrate that severe accidents cause no off-site radiological consequences that would require evacuation of the public.
The design should envisage measures for performance of containment safety functions in severe accident conditions (in particular, implementation of systems to prevent containment bypass in case of corium spreading outside the reactor pressure vessel, prevent explosive gas concentrations in the containment, prevent containment failures as a result of static pressure increase during severe accidents).
The design should envisage severe accident management measures to comply with criteria established for all potential reactor states and all potential locations of nuclear material.
2. Revision and establishment of larger safety margins for extended range of potential natural and human-induced hazards/combinations of hazards.
The design should justify safety margins relative to the extended range of potential natural and human-induced hazards/combinations of hazards. The safety margins for seismic hazards, floods, extreme temperatures etc. should be revised and increased (seismic margin not lower than 100%). The safety margins should allow for potential climatic conditions at least for the design-basis operational period, potential long-term operational period and potential decommissioning period.
3. Long-term performance of safety functions in station blackout and loss of ultimate heat sink.
The design should provide for features to ensure long-term performance of fundamental safety functions in station blackout and loss of ultimate heat sink. The features for long-term performance of fundamental safety functions should rely on the use of alternative independent water and power supply sources.
The design of safety systems should give priority to passive systems that do not require human intervention and do not depend on external sources of energy and information. The design should justify the robustness of these systems within the timeframe needed to overcome the accident active phase.
Following the SSTC NRS report, presentation of the Public Corporation Engineering Company Atomenergoproject and subsequent discussion, the SNRIU Board states the following:
- safety criteria and requirements for nuclear installations are currently revised by international organizations and leading nuclear states, primary attention being paid to the enhancement of requirements for power units to be constructed;
- in accordance with modern approaches and in the light of the Fukushima-1 accident, new NPP designs should demonstrate power unit safety for the entire range of hazards including severe accidents and envisage features for long-term performance of safety functions, in particular, in loss of off-site infrastructure;
- approaches to identifying margins for seismic hazards, floods, extreme temperatures etc. should be revised to substantially increase the margins in line with current international requirements, taking into account tendencies to climatic changes in the world and, in particular, in Ukraine.
In the above regard, the SNRIU Board resolves to:
1. Approve SSTC NRS proposals on improvement of NPP safety requirements as a basis for further revision of regulations and standards on nuclear and radiation safety.
2. Recommend the National Nuclear Operator Energoatom to consider the above requirements in the designs of Khmelnitsky NPP units 3 and 4 without expecting the introduction of new regulations and standards on nuclear and radiation safety.
3. Entrust the Nuclear Installation Safety Department together with SSTC NRS with conducting expert and public discussions of the:
- WENRA document Safety of New NPP Designs;
- SSTC NRS proposals on improvement of NPP safety requirements as the first stage in public discussion of new regulations on nuclear and radiation safety.
Board Chairperson O. MYKOLAICHUK