ASN adapts to innovative SMRs

Whereas siting of a new power generating reactor is one of the aspects of the project which can to a certain extent be a choice, this is not the case for numerous SMR projects.
 
Indeed, in the case of a SMR dedicated to industrial heat production, the site is determined by the location of the customer to whom it will be delivering the energy. Numerous SMR projects are thus aiming for deployment on industrial sites located near to or even within urban areas.
 
This type of siting near to densely populated or industrial areas is being envisaged by the project developers because these reactors are likely to be able to achieve safety levels significantly better than those of today’s large power generating reactors. The low power to be removed in the event of an accident should make it possible to combine passive and active safety systems, leading to increased diversification of the safety provisions, longer grace periods ^[1] and better protection of the containment barriers. In addition, some of the new technologies proposed have specific characteristics (such as the intrinsic containment performance of the particular fuels of high-temperature reactors), which also make it possible to envisage a significant reduction in radioactive releases in the event of an accident, even the most severe.
 
Even if these reactors can in principle achieve a higher safety level than those of the high-power electricity generating reactors, ASN considers that the safety objectives to be attained must be defined before envisaging such siting close to population centres.
 
ASN thus set up a pluralistic working group to consider the reinforced safety objectives to be defined before envisaging such siting choices.

In order to optimise preparations for any creation authorisation applications for these various innovative reactor projects, and in order to mobilise resources proportionate to the level of development maturity of each project, a four-phase framework of incremental technical exchanges was set up.

Phase 1: Screening phase

During a short meeting, the project developer is asked to present the following to ASN and IRSN:

• the main characteristics of its reactor project (technology, power, form of energy output, size of target market in number of reactors, type of site, etc.),
• the state of progress of the reactor design and its development schedule,
• the current technical and financial capacity of the company developing the project, along with its growth plan (calls for funds and staffing).

Following this first prospective contact, the possibility to start phase 2 is considered only if the project developer fulfil the following three readiness criterion, otherwise the project developer is invited to asked later on for a new prospective meeting:

1. Minimum maturity of the technical project:
   the project developer has an initial complete conceptual design of its project;
2. Project developer’s capacity to conduct technical exchanges: the project developer has a sufficient in-house technical team (estimated at about twenty engineers) to be able to carry out technical exchanges with ASN and IRSN on all the technical topics associated with the safety case of its reactor;
3. Minimum financial security of the project developer: the company developing the project has sufficient financial guarantees to back up its development for at least the coming 18 to 24 months.   

Phase 2: Project preparatory review

Once the project maturity is considered to be sufficient with respect to the three above-mentioned criteria, a cycle of thematic technical meetings is scheduled.

By means of presentations and Q&A sessions, the purpose of this cycle of meetings is to obtain a precise overview of the project. These meetings more particularly help to obtain an understanding of its particular design, paint a picture of the knowledge both available and still to be acquired, and clearly identify the main safety orientations of the project.

This phase entails a first level of mobilisation by the IRSN specialists, but simply constitutes an exchange of information in preparation for future assessments. At this stage neither ASN nor IRSN expresses any technical position on the project.

Phase 3: Pre-licensing of the fundamental safety options of the project

Pursuant to Article R. 593-14 of the Environment Code, before finalising the detailed design of its reactor, the project developer that intends to apply for a creation authorisation procedure can ask ASN for its opinion on some or all of the fundamental aspects of its project.

With regard to these innovative reactor projects, ASN recommends that the project developers take advantage of this pre-licensing step. This step enables initial technical assessments to be started and enables the positions of the regulator to be obtained on a jointly agreed list of identified high-stakes subjects highlighted during the preparatory review phase.

Phase 4: assessment of the Creation authorisation application

Finally, once the detailed design of the reactor project is ready, a submission of a creation authorisation application can be envisaged.

This phase represents a new step in the increasing commitment of resources by ASN and IRSN. Following the complete technical evaluation of the project, there will also be an evaluation of the characteristics of the planned site and a programme of inspections of the applicant, who acquires the de facto status of licensee, notably with the aim of checking its management system and its ability to manage subcontracting.

Lightbox

Despite the already high level of harmonisation both internationally, with the safety standards from the International Atomic Energy Agency (IAEA), and at the European level, with the safety objectives and reference levels adopted by the Western European Nuclear Regulators’ Association (WENRA), each project to build a reactor model in a new country generally leads to modification of the original design to adapt to the national regulatory context and the requirements of the local licensee.

Lightbox

Although the cost of these adaptations remains acceptable in the case of large nuclear power reactors, this is not necessarily the case for SMRs, for which the business model is based on mass production to reduce costs and achieve the profitability threshold, thus implying that a given model can be authorised by several countries.

In order to remove potential obstacles to the development of these new small reactors, ASN and IRSN are participating in several international initiatives (IAEA, NEA, WENRA, etc.).