REPORT FROM THE COMMISSION TO THE COUNCIL AND THE EUROPEAN PARLIAMENT

Operation of the High Flux Reactor in the years 2014-15

On 13 November 2012, the Council adopted a four-year (2012-15) supplementary research programme for the HFR , to be implemented by the Joint Research Centre (JRC) on the operation of the high flux reactor (HFR) located in Petten, The Netherlands. Under Article 4 of this Council Decision, the Commission must keep the European Parliament and the Council informed by producing reporting on the implementation of the supplementary research programme. A mid-term report has already addressed the 2012-2013 period . and therefore this final report will address the remaining 2014-2015 period.

In operation since 1961, the HFR reactor provides a variety of irradiation location possibilities (reactor core, reflector region and in the poolside).

The main objectives of the supplementary research programme are:

·To ensure the safe and reliable operation of the HFR, in order to guarantee the availability of the neutron flux for experimental purposes.

·To allow an efficient use of the HFR by research institutes in a broad range of disciplines: improvement of the safety of nuclear reactors, health including the development of medical isotopes, nuclear fusion, fundamental research and training, and waste management including the possibility to study the safety issues of nuclear fuels for reactor systems of interest to Europe.

The HFR is used for the commercial production of radio-isotopes and also acts as a training facility for doctoral and post-doctoral fellows, allowing them to perform research activities through national or European programmes.

1. Safe operation of the HFR

The European Atomic Energy Community (Euratom) is the owner of the HFR (for a lease of 99 years). The HFR reactor is operated by the NRG (Nuclear Research and Consultancy Group) which operates and maintains the plant and manages the commercial activities around the reactor. It has an operating licence granted by the Dutch national regulator KFD (Kernfysische Dienst). As for nuclear power plants, the HFR is subject to legally required 10-year periodic safety reviews which are performed by the NRG.

The 2014-15 period was characterised by one safety-related event (second half of 2015) that affected the availability of the neutron flux.

After an unplanned shutdown period of about 4 months, the HFR returned to service in February 2014. The cycle pattern consisted of a scheduled number of 216 operation days, scheduled 4-day reactor stops and a longer shutdown period of 65 days in October and November 2014. This corresponds to an actual availability of almost 100% with reference to the original scheduled operation plan. Nominal power in this period has been 45 MW.

The HFR was scheduled to operate for 9 cycles in 2015, with 271 planned full power days but only 230 were realized. The main cause for the lost full power days was the cancellation of cycle 2015-08 in October 2015. This cycle was skipped because of a deviation in the control rod system performance. Inspection and analyses revealed a marginal play in one of the reactor control rods used to adjust the reactor power. While this play did not affect the functionality of the control rod nor reactor safety in any way, a new procedure for assembly, commissioning and maintenance/inspection of the control rods was developed preventively to avoid such effects in the future. This was then included in the safety case which was evaluated by the Reactor Safety Committee and by the Autoriteit Nucleaire Veiligheid en Stralingsbescherming (ANVS) - the Dutch nuclear regulator. The ANVS provided a formal statement of no objection to reactor restart. The HFR was safely restarted in December 2015. In close cooperation with rivet experts and after a technical visit to the SAFARI reactor in South Africa (of which the control rods have a similar design) it was also decided to also improve the structural design of the control rod. The new design will make use of different rivets to improve the safety margin. Next to that, also the control rod guide seats will be improved by making use of another bearing material. Implementation of these modifications will be implemented in between 2018 and 2019.

Nominal power in this period has been 45 MW.

During the reporting period (2014-2015), the annual 30 MW reactor training for the operators and the yearly flux measurements have been carried out as scheduled.

In 2014 and 2015, maintenance activities consisted of the preventive, corrective and breakdown maintenance of all systems, structures and components (SSC) of the HFR, as described in the annual and long-term maintenance plans. These activities were carried out to ensure the HFR’s safe and reliable operation and to prevent inadvertent shutdowns caused by insufficient maintenance. The following activities were successfully completed:

·Scheduled regular preventive and corrective maintenance;