ASN determines that the Osiris and Isis experimental reactors (INB no. 40) may continue to operate

In its assessment of 27 May 2011 (2011-AV-0121), ASN determined that the Osiris reactor can continue operation until 2015, at which time the reactor should be shut down in compliance with ASN Commission decision 2008-DC-0013 of 16 September 2008. For its part, the Isis reactor can continue to operate for an additional ten years from the date on which its most recent safety review file was submitted, i.e., until 2019. The two experimental reactors constitute basic nuclear installation 40 operated by the CEA in the municipality of Saclay (Essonne)[1].

The CEA is however required to respond to the ASN's requests, which were formulated after analysis of the facility’s safety review file submitted on 30 March 2009. In addition, ASN's assessment does not prejudge the conclusions of the complementary safety assessments that were begun following the Fukushima accident.

In France, the operating license for a basic nuclear facility does not set a time limit for service life. In this context, article 29 of the law of 13 June 2006 concerning transparency and security in the nuclear field (TSN law) requires the operator of a basic nuclear facility to submit the facility to a safety review every ten years, after which ASN takes a position on whether it will continue to operate.

The safety review provides an opportunity for an in-depth examination of the facility’s situation in order to verify that it complies with all applicable rules (compliance review) and to improve its safety level by taking into consideration changes in requirements, practices and knowledge concerning nuclear safety and radiation protection as well as national and international operating experience feedback (safety assessment). The safety review also verifies that various phenomena associated with ageing facilities will be managed for at least ten additional years.

In order to take into account the first lessons from the Fukushima accident, ASN adopted, on 5 May 2011, decision 2011-DC-0224 directing the CEA to perform a complementary safety assessment on the Osiris and Isis reactors in view of the accident. The assessments concern all basic nuclear installations which are not in the decommissioning phase and includes experimental reactors. The CEA will submit an initial report to ASN on the results of the assessment on the Osiris reactor on 15 September 2011 and a second on results from the Isis reactor no later than its next safety review.

[1] The Osiris reactor, which has a thermal power of 70 MWth, is used to irradiate fuel elements and structural materials from nuclear power plants and produce radioelements and doped silicon.

The Isis neutron model, with a thermal power of 700 kWth, is used for teaching.