When licensing a new nuclear facility, a preliminary system description shall be developed for each system of the facility. This document is called the Preliminary Safety Analysis Report (PSAR). The document and its appendices shall be submitted to the Radiation and Nuclear Safety Authority (STUK) for approval when applying for a construction licence for the facility. Later, when applying for an operating licence, the documentation in question is updated into the Final Safety Analysis Report (FSAR).

At operating nuclear facilities, system-level FSAR documents are continuously maintained and any necessary changes are made to them according to plant modifications. As explained in the previous section of the blog series, a conceptual plan must be drawn up for plant-level modifications. A conceptual plan shall also be made for an individual system if the design basis of the system changes.

If a conceptual design plan for a modification has been drawn up or if the modification affects the safety functions of the system, a pre-inspection documentation (ETA) package shall also be prepared. It is a document package equivalent to the PSAR for new nuclear facilities. An ETA is a system-level document package designed to identify and describe the effects of a planned plant or system modification on the system and related systems and to define system-level requirements. The purpose of the ETA is, above all, to justify the acceptability of the planned modification from the perspective of nuclear safety.

An ETA package typically includes a main document that describes the modification comprehensively from different perspectives, taking into account all fields of technology. The ETA shall include at least the same information as the PSAR which is submitted at the construction licence stage of a new nuclear power plant. However, it is often more practical to draw up a so-called red-marker FSAR, which describes the effects of the modification on a valid FSAR. The acceptability of the modification from the perspective of nuclear safety can be examined in a separate safety assessment or it can be combined with the main document.

The main ETA document typically contains at least a summary of the analyses justifying the acceptability of the modification, but it may also contain the specific safety analysis reports that provide said justification in detail. In addition, system-specific qualification and quality plans and requirement specifications are drawn up in connection with the ETA.

The pre-inspection documentation of safety-classified systems shall be submitted to STUK for approval, and information related to similar EYT/STUK-class system modifications shall be submitted for information. For other system modifications, a summary description of the modification shall be submitted to STUK for information, presenting the purpose and main features of the modification.

Plant- and system-level modifications may cause changes at the equipment level. If new types of equipment are required that have not yet been qualified for the facility in question, or if the equipment requirements change from those previously qualified, the equipment shall be validated in accordance with the requirements approved in the ETA.

Platom has several experts with experience in both construction projects of new nuclear facilities, preparation of PSAR document packages, implementation of plant- and system-level modifications of operating nuclear facilities and preparation of ETA document packages. Platom has expertise in licensing and supporting modifications to automation, electrical and process systems. Platom’s experts also have solid expertise in the preparation of safety analyses, for example with Apros software, and in the planning and implementation of qualification and quality management. Acting as an independent expert, Platom may also support the licensee in preparing the safety assessment.