Page 106 - ILLS Annual Report 2018

REACTOR OPERATION 2018
Reactor operation
Three reactor cycles were completed in 2018, using three fuel elements and providing a total of 152 days of scientific activity.
Cycle n°
Start of cycle
End of cycle
Number of days of operation
Number of days scheduled
Power in MW
Number of unscheduled shutdowns
182
28.02.18
26.04.18
55.5
56
40, then 58.3
1
183
22.05.18
05.07.18
44.3
51
52.6
0
184
03.09.18
28.10.18
52.5
52
51.6 then 35
1
Total
152.3
159
49.2
2
The end of the second cycle had to be brought
forward due to a defect on one of the cladding failure detection systems; the other systems that make up the protection circuit remained operational. In addition, two unscheduled reactor shutdowns occurred:
1.The first was due to disruptions to the electricity supply.
2.The second was an automatic shutdown. A defect on the pressure-measuring channel of the horizontal cold neutron source led to an emergency shutdown. The reactor was restarted using the second measuring channel.
The winter shutdown was used for a host of important maintenance and other operations:
• Replacement of beam tubes H3 and H8
• Removal of beam tube H6/H7 and its replacement with two sealing plugs
• Work on the emergency core reflood (CRU) and water makeup (CES) systems
• Work on the groundwater circuit (CEN)
• Replacement of beam tube V7
• Replacement of the start-up source and installation of start-up source n° 5
• Commissioning of the instrumentation and control units in the reactor control room and the emergency control room (PCS3) for the emergency cooling circuits (CRU, CES, CEN)
• Wiring of the control unit, located in the PCS3, of the system for manually ‘dropping’ fuel elements onto the floor of the transfer canal
• Leak testing of the reactor building (an initial test was carried out in March 2018 prior to the installation
of the truck entrance airlock, and a second test was performed in November 2018 with the new truck entrance airlock in place)
• Replacement of the pyrotechnic valve VPNF 3AM (on the light water pool side)
• Qualification of handling cask WF2: testing of the fuel element emergency drop system
• Major maintenance work on the second main diesel generator
• Implementation of new hafnium safety rods • Replacement of beam tubes H4 and H10.
The post-Fukushima programme has been completed. The safety of the reactor is now guaranteed even in the event of an extreme earthquake-plus-flood scenario following a breach of the dams upstream of the ILL. Our installations now comply with requirements well above the previous design basis.
At the end of 2018 we submitted the last set of documents for our ten-yearly safety review, which will determine whether any further work is required to ensure that the ILL reactor installations comply with the latest safety standards. Requests for additional work are likely to be limited given the extent of the reinforcement work already carried out under the Reactor Refit programme (2002 to 2007) and the post-Fukushima programme (2012 to 2017). The safety authorities will begin their examination of the safety review report at the very beginning of 2019.
ANNUAL REPORT 2018