RRFM 2009 Transactions - European Nuclear Society

O 75 Bignan.doc - DI - 4 / 10 20/02/2009
• Effective transient devices for safety studies, a major scientific
challenge
• Hot cells for the current operation (preparing the experiment, non
destructive exams) and alpha cell for Safety fuel experiments
• On line instrumentation and control (more data, better management,
extrapolation capability with modelling)
• On line fission product measurement laboratory for gas and liquids
Last but not least, the JHR performance relies on the JHR experimental devices fleet. The
starting of the development phases is related to the maturity of the demand and depends on
the complexity of the device to set up 1 .
3 Preliminary Safety Analysis of the reactor fuel
In order to comply with the evolution of safety requirements and to guarantee long term
operations, the construction safety standards of JHR have been significantly improved
compared to MTRs built in the 60s.
• The safety approach of JHR takes into account a systematic assessment (and
the implementation of necessary design modification) of external or internal
hazards on the nuclear buildings.
• Furthermore, the JHR confinement is designed to face severe accident
conditions. The so-called “Borax accident” (hypothetic beyond design reactivity
accident with explosion and core melt) is taken into account in the design of the
containment and the water bloc.
• In addition, the JHR safety approach addresses irradiation devices as a
potential aggressor of the facility. This problematic involves potentially energetic
experiments (PWR loops, safety tests) and/or tests with significant radio
isotopic content (eg. Tests on minor actinides).
Under the French laws and as part of the licensing procedure leading up to the decree
authorising setting-up JHR large-scale nuclear facility, an examination of the Preliminary
Safety Analysis Report (PSAR) by the French Nuclear Safety Authority (ASN) has led to the
preliminary approval of the reactor fuel for the driven core.
3.1 Background and updated practices
In the past, the authorisation to use a fuel in a French research reactor was obtained on the
basis of a qualification irradiation, which involved baking fuels samples under normal reactor
conditions. This authorisation was generally dependent on the feedback provided by its use
in the reactor or via the irradiation of several fuel elements prior to total core conversion. This
phase helped to validate the expected fuel behaviour under operating conditions. However,
only normal operating conditions were tested.
For non-normal conditions, numbers of tests were performed on MTR fuels in the 1960s.
They involved aluminium-based fuel plates containing highly-enriched uranium. Reactivity
insertion accidents (RIA) and their behaviour were especially studied in the USA using the
SPERT reactor and in France using the CABRI reactor. These tests have not been updated
since this time.
1 For more information about these developments see the presentation of Daniel Parrat on RRFM 2008
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