NUCLEAR POWER PLANT A-1 BOHUNICE
NPP A-1 Bohunice with heterogeneous reactor for natural uranium moderated by heavy water and cooled by CO2 had been in operation for 4 years and was definitely shut down after an accident in February 1977 (INES level 4). The current concept for its decommissioning was adopted by a government decision of 1992 and its first phase is being realized according to the plan submitted in 1994-5.
In 1999 the main activities at NPP A-1 Bohunice were focused on completing of the spent fuel preparation for transport. Preparation of the remaining 32 fuel assemblies was successfully completed on the equipment for fuel preparation for transport to the Russian Federation. Assembly of the so-called long storage (determined for storage of high active radwaste) was completed as well as tanks for chrompik storage. Vitrification of chrompik, decontamination and dismantling works continued in the area of the reactor building. After modifications, in 1999 the large capacity decontamination facility and fragmentation facility for fragmentation and further processing of metal waste were again under operation.
Assessment activity of UJD was focused on evaluation of safety documentation of the above-mentioned activities and on approval of technical specifications. Based on review of the "Decommissioning Plan of NPP A-1 Bohunice -phase 1 "and the concept of decommissioning for all following phases, in compliance with the Atomic Act UJD issued an approval for the decommissioning of NPP A-1 Bohunice -phase 1. In connection with this phase, according to the law No. 127/1994, UJD also reviewed the Report on environmental impact assessment of the decommissioning of NPP A 1 Bohunice. In 1999 there were 4 operational events registered at NPP A-1 Bohunice, of which one (loss of electrical power supply with no violation of technical specifications) was assessed as level 0 on INES. The other 3 events were out of the INES scale.
Inspection activity of UJD at NPP A-1 Bohunice was realized mainly in a form of routine inspections, of which there were 58 in 1999. Inspections focused on preparation of spent nuclear fuel for transport, nuclear safety during decommissioning of NPP A-1 Bohunice, radwaste management, reliability of operation and product quality of the vitrification facility, readiness of fragmentation facility and the large capacity decontamination facility for operation and contaminated soils management. Inspection activity focused also on qualification and training of staff, recording of technical specifications, meeting the quality assurance program, readiness of IT systems for transition into year 2000, and documentation of the internal emergency plan. Among the characteristic shortcomings found during inspections remains an insufficient internal control of documentation and not meeting the deadlines for completion of individual works. Measures imposed by UJD to the operator in 1999 have been continuously met.
INTERIM SPENT FUEL STORAGE BOHUNICE
Interim spent fuel storage Bohunice is used for interim storage of spent fuel produced in NPP V-1 and NPP V 2 Bohunice. Its original storage capacity of fuel assemblies proved to be insufficient, and therefore the operator adopted a decision to expand the storage capacity in 1996. Increased storage capacity of fuel assemblies has been achieved by storing the spent fuel in new types of storage baskets with 48 fuel assemblies and by tighter placement of storage baskets in the existing pools of interim spent fuel storage Bohunice. Part of the interim spent fuel storage reconstruction is also its seismic strengthening. Reconstruction of interim spent fuel storage Bohunice, started in 1998, continued also in 1999, so that it can be put into commercial operation at the beginning of 2000.
Within the reconstruction works on interim spent fuel storage Bohunice UJD reviewed operative programs of facilities reconstruction having impact on nuclear safety, as well as programs of their pre-complex and complex testing in the scope of reconstructed technology systems. In all cases UJD issued a positive statement to realization of the mentioned programs as well as to a complex test of interim spent fuel storage Bohunice after reconstruction. Results of tests were submitted for review to UJD. Temporary limits and conditions were prepared and approved by UJD to secure nuclear safety of stored fuel for the period during reconstruction. Final Safety Analysis Report of the reconstructed interim spent fuel storage Bohunice was submitted to UJD for review at the beginning of September 1999. This report is currently under review.
Due to the fact that the original storage capacity of interim spent fuel storage Bohunice was exhausted in the second half of 1999, the operator applied for an approval to use the new type of compact baskets for storage of spent fuel assemblies already in 1999. Based on the documentation proving that the conditions of nuclear safety were met, especially conditions of undercriticality of fuel stored in the compact baskets, and successful results of tests on the reconstructed spend fuel residual heat removal system, UJD issued the relevant approval.
The fuel was charged into the new type of compact baskets at the interim spent fuel storage Bohunice already during the phase 1 of the Program of gradual commissioning of the reconstructed interim spent fuel storage Bohunice. At the end of 1999, the spent fuel was thus stored in 17 compact baskets of KZ-48 type.
During the year there were carried out several inspections at the interim spent fuel storage Bohunice concentrating on checking of compliance with the LaP and operational instructions for operation of individual equipments. There was no violation of conditions of nuclear and radiation safety found. UJD evaluated the operation of the interim spent fuel storage Bohunice in 1999 as safe.
TECHNOLOGY FOR TREATMENT AND CONDITIONING OF RADIOACTIVE WASTE BOHUNICE
Nuclear facility "Technology for treatment and conditioning of radioactive waste "Bohunice is determined for treatment and conditioning of low and intermediate radioactive waste in a form suitable for disposal (so called waste package) in the National radioactive waste repository. Nuclear facility "Technology for treatment and conditioning of radwaste "consists of:
- Bohunice Conditioning Center
- Bituminisation facility PS 44
- Bituminisation facility PS 100
- Cementation facility.
The main part is the Bohunice Conditioning Center with the technology of super compaction, cementation, fragmentation and incineration of radwaste. In 1999 non-active tests of these technologies continued and at the end of the year UJD issued on approval for commissioning of this center.
Two bituminisation facilities are also the part of the nuclear facility "Technology for treatment and conditioning of radwaste ". The first one (PS 44) , which has been in operation since 1995, was used for conditioning of liquid concentrates from NPP V 1, NPP V-2 and NPP A 1 Bohunice. The second one (PS 100) completed the phase of non-active tests in 1999. Cementation facility, was commissioned in 1986 with the purpose to solve possible extraordinary situations connected with the production of large quantities of liquid radwaste. The technology is permanently shut down.
Assessment activity of UJD was concentrated on review of safety documentation submitted by the operator in connection with the application for issuing a resolution on the approval of UJD for commissioning of the Bohunice conditioning center. In 1999 there were two events registered and assessed by UJD at the facilities for treatment and conditioning of radwaste with no effect on the nuclear safety of these facilities.
Routine inspection activity of UJD was focused on observance of nuclear safety during production of radwaste packages, on meeting specification of safe transportation of radwaste and on decreasing fire risk in the process of radwaste bituminisation. In 1999 there were altogether 49 routine inspections, of which 13 at the bituminisation facilities and 36 inspections on the Bohunice conditioning center.
The aim of the team inspection was a complex verification of readiness of the Bohunice conditioning center for the phase 1 of commissioning. Measures imposed were focused on radwaste flow stream characteristics in the process of treatment and conditioning.