DS557 - Site Evaluation for Nuclear Installations

Status: STEP 3

Revision von SSR-1

Beteiligte IAEO-Komitees: NUSSC, RASSC, WASSC, TRANSSC, NSGC, EPReSC

Safety Requirements

Zurück zur Übersicht "In Entwicklung befindliche Safety Standards"

Background Information

The revision of the existing document will impact all current chapters, with particular focus on ensuring its applicability to a wide range of emerging technologies, including, but not exclusively, the following: small modular reactors (SMRs), transportable reactors (e.g. micro-reactors) underground installations, advanced reactors, fusion reactors, and others.

The revision will also ensure full compatibility with the IAEA Safety Fundamentals and other related Safety Requirements documents.

The proposed modifications will be reviewed by expert teams tasked with revising the requirements document. These revisions aim to provide Member States with comprehensive and up-to-date safety requirements that reflect the general consensus among States.

In general, the following areas have been identified as requiring revision, improvement or even new development:

• Technology neutrality: Site safety assessments should explicitly consider the compatibility between the site, number and type of installation to be built, and account for specific conditions associated with the selected reactor technology (e.g. SMRs, transportable NPPs, underground, etc.) must be explicitly addressed.
• Development of extreme hazard scenarios for the safety assessment of design: There is a need to clarify the hazard characteristics to be used in the safety assessment of all levels of defence in depthDepth (DID) for external event scenarios in all types of nuclear installations (especially. those other than NPPs). Additionally, events which refer to beyond-design-basis scenarios must be characterized to ensure a comprehensive safety assessment during the design phase, focusing on evaluating robustness and resilience.
• Characterization of low-probability scenarios: There is a need to improve the management of large uncertainties associated with low-probability scenarios and the development of models to project these risks over time.
• Site characterization techniques: Updated techniques and guidance on the application of the graded approach are required for all phases of a plant's life, including site selection, site evaluation, construction, operation (incl. periodic safety review) and decommissioning.
• Identification of “bounding site” conditions: clarify how bounding site conditions for the design of standardized  plants should be considered  in the site-specific licensing process in view of the design safety assessment of the standardized plant for any specific site.
• Safety–security interfaces: It is crucial to address safety and security interfaces since the stage of development of design basis for the installation, particularly in the establishment of design basis threats (DBT) and design basis external scenarios respectively, considering their role in the overall site assessment process.
• Site related issues during the operating life of the installations: Develop guidance on monitoring systems and reliable sources of information on site hazards, especially addressing meteorological and hydrological hazards, to support proactive operator actions, hazard review on the occasion of the periodic safety review, management of emergency actions at the site and in the site vicinity when affected by extreme external event scenarios.