PLANNING ACTIVITIES FOR ANPP DECOMMISSIONING

摘要

The Armenian NPP consists of two WWER-440, model 270 pressurized water reactors. After an earthquake in northern Armenia in December 1988 both units were shut down for safety reasons: Unit 1 in February 1988, Unit 2 in March 1989, respectively. Unit 2 was restarted in November 1995 after a number of safety upgrades. Unit 1 remains in a long-term shutdown mode. The design lifetime of Unit 2 expires in 2015. Opportunity to shutdown earlier has been discussed in the last years. In particular a statement has been issued by EC asking for an early shutdown of Unit 2 in exchange for the TACIS support in implementing the safety upgrades in a short term. Currently the safety improvement program is being successfully implemented in the framework of US DOE and TACIS assistance. At the moment the date of the permanent plant shutdown is not specified.As with many older reactors throughout the world, a decommissioning plan has not been developed for Armenian NPP at the design stage. After shutdown of ANPP in 1988-1989 the radiological characterization campaign at Unit 1 had been carried out.Recently two studies in the decommissioning area have been performed for ANPP.The first one has been carried out under the US DOE Assistance Program. The purpose of this study was to identify and evaluate feasible decommissioning options for ANPP. Some critical issues related to the waste management had been specified and the near-term activities within this project will be focused on issues of waste characterization and information data base creation as an important prerequisite to manage waste safely. The model used to calculate many of the decommissioning costs was NRC CECP reprogrammed for WWER NPPs. The second study had been carried out in the framework of TACIS project "Assistance to Energy Strategic Center". The purpose of the study was to select the best strategy to phase-out and decommission the ANPP and evaluate conditions, implications and consequence of this decision. A suggested solution was a choice of SAFSTOR as a viable decommissioning option.Spent fuel management is not considered part of decommissioning; however it can strongly affect the decommissioning strategy. Currently the spent nuclear fuel is being stored on site in pools and in a newly constructed NUHOMS storage facility built by FRAMATOME under license of USA Transnuclear West Company. The facility includes 11 horizontal storage modules (HSM). Each HSM has a capacity of 56 non-failed fuel assemblies. A capacity of the existing dry storage facility is not sufficient to accommodate all spent fuel generated during plant operation. However, the NUHOMS concept is modular and it is possible to increase the storage capacity. The facility is designed for 50 years storage of spent nuclear fuel.In any case, these studies should be considered as an informative basis only. Much more additional information should be collected and the detailed characterization survey, i.e. the comprehensive engineering and radiological survey, conducted to have sufficient data for all further planning activities.