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Design Safety (DS)​​​​


The objective of the Technical Safety Review of Design Safety (TSR-DS) is to review the design safety of nuclear power plants (NPPs)[1] against the IAEA Safety Standards and assist the Requesting Party to review the safety documentation for NPPs during any of the major stages of the licensing process, i.e. during the design, construction and commissioning phases as well as during operation phase.

The IAEA Safety Standards reflect international good practice on design and design enhancements of NPPs. The designs of many existing NPPs, as well as the designs for new nuclear power plants, have been enhanced to include additional measures to mitigate the consequences of complex accident sequences involving multiple failures and of severe accidents. Complementary systems and equipment with new capabilities have been back fitted to many existing nuclear power plants to aid in the prevention of severe accidents and the mitigation of their consequences. Guidance on the mitigation of the consequences of severe accidents has been provided at most existing nuclear power plants. The design of new nuclear power plants now explicitly includes the consideration of severe accident scenarios and strategies for their management. Requirements related to the Member State system of accounting for, and control of, nuclear material and security related requirements are also taken into account in the design of nuclear power plants. Integration of safety measures and security measures will help to ensure that neither compromise the other.

Click next​ to consult the TSR-DS Review Guidelines, the reference document for the IAEA Technical Safety Review (TSR) – Conceptual Design Safety (DS). ​


The scope of the review is defined by the Requesting Party in consultation with the IAEA and should typically take into consideration aspects such as:

  • Areas of the design subject to the review;
  • The available documentation (can range from a PSAR to a FSAR);
  • The specific focus of the review, eg. overall design, upgrade of the design of certain systems, significant design modifications, etc;
  • Site specific information.

The framework of TSR-DS review is based on the latest design Safety Standards and good practices as documented in the IAEA Safety Standards, including:

  • Fundamental Safety Principles (IAEA Safety Standards Series No. SF-1);
  • Safety Requirements on Safety of Nuclear Power Plants: Design (IAEA Safety Standards Series No. SSR-2/1 (Rev. 1))
  • Safety Requirements on Leadership and Management for Safety (IAEA Safety Standards Series No. GSR Part 2);
  • Safety Requirements on Safety Assessment for Facilities and Activities (IAEA Safety Standards Series No. GSR Part 4 (Rev. 1);
  • Safety of Nuclear Power Plants: Design (IAEA Safety Standards Series No. SSR-2/1 (Rev. 1).

Set of IAEA Design Safety Guides is considered as supporting information for purposes of clarification of the requirements used as the basis for the review.


The TSR-DS offers interested Member States a number of benefits including:

  • Experts invited to carry out the service are internationally respected and independent with no conflict of interest with the Requesting Party, which ensures respect for the findings and provides assurance that recommendations will be addressed by the Requesting Party. Thus, respected and independent review increases confidence of all stakeholders (including public), both local and international, that the design meets strict international requirements and ensures the highest Safety Standards that can reasonably be achieved. In addition to these benefits, undertaking the TSR-DS Service ensures that any gaps in the coverage of safety requirements in the design were identified and adequate attention was paid to known safety issues.
  • Results of comprehensive design assessment provided by IAEA TSR-DS Service provide reliable and valuable information for use in justification of the design safety to regulators by providing a high-level comparison of the interpretation of IAEA requirements with the particular Member State regulations.
  • Discussions and results of the TSR-DS Service can be useful to Requesting Party to understand the latest interpretation of requirements and current best practices in meeting them and help entities responsible for design to avoid false interpretation of concepts and requirements relevant for design. 
  • Follow up missions can be requested to explore identified issues in more depth and provide assurance that actions taken to address the TSR-DS results are timely and adequate.
  • Provides an independent check that modifications implemented to the design do not have an adverse impact on the safety of the nuclear installation.
  • Enhances the understanding of how operational experience is changing the understanding of the safety of a nuclear installation and reinforces adaptation of design changes to address lessons and issues that arise during operation.
  • Provides independent review of the strategy to address major concessions arising during construction and provides input to the strategic decisions on power station designs to implement at a particular location.

DESIGN SAFETY (DS) Reviews Conducted



Member State



DS documentation of Rooppur




DS documentation of
• Rivne
• South Ukraine
• Zaporozhe
• Khmelnitski




DS documentation of Armenian (Follow-up)




DS documentation of Khmelnitski




DS documentation of Kozloduy (Follow-up)




DS documentation of Kozloduy




DS documentation of Chashma




DS documentation of Armenian



[1] The scope of TSR-DS is referring to a site-specific design (for a specific NPP) while the TSR-GRS scope refers to a generic conceptual or basic design.