Olkiluoto NPP
Loviisa 1 was shut down to repair a leaking flange seal in the steam generator In February, a
4.1.6 Spent nuclear fuel storage and low and intermediate-level waste
STUK reviewed, in accordance with the inspection programme, the low- and intermediate-level waste management and final disposal of waste materi- als at the Loviisa power plant. The inspection of low- and intermediate-level waste management fo- cused on the situation of the project for developing the handling of low- and intermediate-level waste, the arrangements at the liquid waste solidifica- tion facility, waste accounting, organisation and instructions. Following the inspection observations, STUK required the Loviisa power plant to assess the rusting and corrosion mechanism of low-level waste barrels placed in the VLJ repository, as well as the impacts that the deteriorating condition of the barrels will have on nuclear waste manage- ment and its safety.
In October, STUK carried out an inspection of fi- nal disposal facilities for waste at the Loviisa pow- er plant. It covered the maintenance procedures at the plant site, the repairs and modifications car- ried out and the results of inspections performed by the power company. The latter also included the results of groundwater chemistry measurements taken from the bedrock of the disposal facility, as well as the hydrological and rock-mechanical monitoring measurements. No requirements were imposed following the inspections.
The processing, storage and final disposal of low- and intermediate-level waste (so-called op- erating waste) at the Loviisa power plant were carried out as planned. The volume and activity
Quantities of spent fuel and low- and intermediate-level waste
The volume of spent nuclear fuel stored on-site at the Loviisa power plant at the end of 2011 was 4,339 assemblies* (522 tU), an increase of 192 assemblies (23 tU). The volume of low- and intermediate-level waste finally disposed of was 1,774 m³. The total increase of volume from 2010 is 93 m³. Approximately 50% of the waste has been finally disposed of.
* The assembly figures do not include the as- semblies in the reactors. The average weight of spent fuel assemblies at the Loviisa power plant is 120.3 kgU.
One event occurred in 2011 in intermediate- and low-level waste management. It was de- tected at the Loviisa power plant in early 2011 that the seepage water collection system of the low-level waste repository contained small amounts of ra- dioactive tritium. Radioactivity had escaped into the system when the drain pipe for water dropping from the ceiling had become blocked and water had run on some waste barrels. The event had no impact on the safety of personnel or the environ- ment. Following the event, Fortum replaced the drain pipes of the seepage water collection funnels on the ceiling of the repository. The activity of seep- age water and condensation water in the ventila- tion system is closely monitored.
STUK-B 147 4.1 Loviisa NPP
of low- and intermediate-level waste in relation to generated electrical power remained relatively low compared with most other countries. Contributing factors include the high quality requirements for nuclear waste management and nuclear fuel, the planning of maintenance and repair operations, decontamination, component and process modi- fications, as well as waste monitoring and sort- ing, which enable some of the waste with a very low radioactive substance content to be cleared from control. In 2011, quantities of maintenance waste below the activity limits and scrap metal were cleared from control at the power plant, with STUK’s approval. In addition, the power plant em- ploys efficient procedures for reducing the volume of waste subject to final disposal.
Construction and commissioning of a liquid waste solidification facility
A solidification facility for liquid radioactive waste has been constructed on the Loviisa plant site. The solidification facility processes the radioactive evaporation residues generated at the power plant and the radioactive ion exchange resins from the purification filters. Prior to commissioning the so- lidification facility, a test programme will be car- ried out and approved to ensure that the solidifica- tion facility systems function as planned. The tests are to ensure, among other things, the functioning of the I&C system, the correctness and adequacy of the information transmitted by the process mea- surement devices, and waste package activity de- termination. STUK approved in 2008 the results of the pre-operational tests carried out using ra- dioactive evaporation residues. Trial operation on the resin waste began in May 2009, but there have been delays due to various reasons, including the unreliable operation of the dosing tank level mea- surement.
In order to continue the commissioning of its liquid waste solidification facility, Fortum has de- signed improvements to the plant’s process sys- tems and instructions. The possibility of liquid waste spreading to the ventilation system from the degassing lines will be prevented by changes in process technology. Improvements will also be made to the tank level measurements.
The HARVALA sub-project of the LOKIT project, intended for increasing the resin storage capacity, has advanced in the liquid waste storage facility.
In the sub-project, the storage capacity of inter- mediate-level resin will be expanded by modifying one low-level ion exchange resin storage tank to be suitable for intermediate-level resin. The radiation protection structures surrounding the tank will be reinforced, level measurements will be added and pipeline connections built. TVO submitted the conceptual design plan for the project to STUK for approval in late 2011.
Expansion of the repository for low- and intermediate-level waste
An expansion of the repository for low- and inter- mediate-level waste was initiated at the Loviisa power plant in 2010. The expansion will comprise Maintenance Waste Facility 3 and a connecting tunnel. The excavation work for the facilities was completed in the early spring of 2011, after which the construction work continued with equipment installations inside the facilities until the end of 2011. The new facility will be used for the sorting and temporary storage of maintenance waste.
According to the statement issued by the Ministry of Employment and the Economy, the expansion could be implemented subject to STUK’s approval and oversight. Maintenance Waste Facility 3 will be commissioned during the first quarter of 2012. The commissioning will require an operating licence is- sued by STUK and a commissioning inspection.
Provisions for the costs of nuclear waste management
In compliance with section 88, subsection 2 of the Nuclear Energy Decree, Fortum provided the Ministry of Employment and the Economy with the revised and supplemented waste management scheme and information on the costs and prices of nuclear waste management measures at the end of June. The update of the waste management scheme includes an index adjustment to the cost and price information as well as an estimate of the amount of nuclear waste at the end of 2011.
STUK reviewed the documents submitted in compliance with the Nuclear Energy Decree and submitted a statement regarding them to the Ministry of Employment and the Economy. In its statement, STUK pointed out the incorrect es- timate of the amount of spent fuel in the waste maintenance scheme of 2010, which Fortum will correct for the next waste maintenance scheme
STUK-B 147 4.1 Loviisa NPP
in 2013. In 2011, Fortum’s liabilities amounted to EUR 968.3 million.