Aftermath of the INES-3 Incident at Paks NPP on 10th April, 2003. Lajos Vöröss Hungarian Atomic Energy Authority 7th Annual Meeting of NERS IAEA, Vienna, 23-24, September 2004. Main Tasks to Perform.
Aftermath of the INES-3 Incident at Paks NPPon 10th April, 2003.
Hungarian Atomic Energy Authority
7th Annual Meeting of NERS
IAEA, Vienna, 23-24, September 2004.
After having stabilised the situation inside the reactor hall there have been two main tasks to perform:
1. Recovery of service shaft No.1 of Unit 2. (SS) where the incident occurred
2. Restart of Unit 2. as soon as possible
- Recovery project and team established at Paks NPP
- Tendering process won by Russian consortium led by TVEL; FRAMATOM had bidden as well
- 6-8 months preparatory, 2-3 months implement phases planned, excluded licensing time - significant delay now
- Special tools for manual removal of debris are to be used
- Manipulation is to be carried out from a movable platform placed above the cleaning tank
- Some experiments to clarify behaviour of debris for planned removal actions performed
Recovery outline – FRA/GER
Recovery outline – RUS
- water level,
- Separation of SS from spent fuel pond and from other
systems of Unit 2.became necessary
- Autonomous cooling device and emergency boron
injection system for SS have been installed
- Mobile water cleaning device (NURES,Finland) was used
to clean the water especially from the uranium and trans-uranium isotopes
- Reliable neutron flux and boron concentration measurement in SS installed
- Increased radwaste storage capacity constructed
- Free positions made available for capsules/cartridges containing debris in spent fuel pool
- Preparatory actions for regulatory licensing process
- regulatory requirements for recovery developed
- review and assessment in large number of modifications and fabrication of equipment performed
- After long-term shut-down status with intact main equipment but contaminated by uranium and trans-uranium isotopes - special cleaning was necessary (completed)
- Interrupted refuelling and maintenance occurred during the incident
- RPV used as temporary storage tank of spent fuel assemblies
- Low enrichment fresh FE supply and rearrangement of spent fuel pool became necessary
- Reuse of cleaned spent fuel assemblies is limited
- Conception for short term operation cycle developed
- refuelling and yearly maintenance completed
- suitable core for operation during the preparatory phase of the recovery is possible (about 4 months long)
- regulatory requirements for restart/operation phases developed, licence given on 16. July, 2004.
- nearly full power operation started on 02 Sept. 2004.
- Keen interest from media and public follows
- IAEA - two international missions provided at Paks NPP
- GAN (Russian Regulator) - on basis of contractual arrangement, focuses to review QA of Russian contractors
- US NRC/IAEA - gives advice to review conditions of restart of Unit 2.
NOTE: In spite of the incident, lifetime extension and power uprating of the units are still insisted on