Karlsruhe Vitrification Plant (VEK) – 2nd Partial Licence

The Karlsruhe Research Center (FZK) and the Karlsruhe Reprocessing Plant (WAK) jointly applied for the construction and operation of a vitrification plant as a supplement to the existing WAK. The purpose of the plant is to solidify the high-level radioactive fission product solution (HAWC) currently stored in the WAK, to fill it into waste canisters, and to treat it in such a way that it can be accepted by interim storage facilities and repositories. The nuclear licence applied for comprising the construction and operation of the VEK is granted in five steps, three partial construction licences and two partial operating licences (TBG).

To prepare a statement under federal supervision, BMU requested SSK to discuss the draft of the 2nd TBG for the VEK. The 2nd TBG includes the setting up of the hot joints to the storage and evaporation plant (LAVA), hot commissioning and hot vitrification operation including the vitrification of the HAWC, the subsequent removal of residual glass material and rinsing of residual contaminated LAVA and VEK components, and taking selected components in the LAVA and the VEK out of operation. “Hot operation” comprises the production of approx. 130 vitrified waste containers and the transport provision of the loaded CASTOR casks on the VEK transport provision area.

The SSK discussions resulted in some indications relating to the draft of the 2nd TBG for the VEK, which are substantiated in detail in the SSK statement.

On account of the high, inhomogeneous neutron dose rate associated with the works on transport provision and with the handling of CASTOR casks, it is deemed necessary to determine the personal dose with the help of dosimeters that are appropriate for measuring neutrons. Furthermore it is suggested to consider using neutron-sensitive dosimeters that can be read by the staff themselves. Altogether, it is stated with respect to the concept and the design aiming at dose restrictions to the staff that there are no concerns about the hot commissioning of the VEK and its operation including the planned handling of the loaded CASTOR casks provided that the outstanding conditions and requirements regarding radiological occupational health and safety are implemented.

As regards the radiation exposure to the population in normal operation due to the discharge of radioactive substances with exhaust air, it was stated that in each case, the potential radiation exposures to the reference persons caused by the licensed discharges were below the limits set out in the provisions of § 47 StrlSchV. Discharges via the water path are not planned. Direct radiation on the plant premises will not increase through the activities in the VEK. It will also be within the variation limit of the underground radiation after operation has been taken up. This will be controlled once again within the scope of the dose rate measurement program.

Incident analyses were carried out to the necessary extent within the scope of the 1st TBG. As a result of investigations carried out now and supplementing considerations on incidents and events with respect to residual risk, the requirements on radiation protection are, thus, considered to be complied with.

As regards emission and immission monitoring it was stated that, compared with the evaluation of the concept in 1998, no further findings have been found that could lead to a different evaluation. The decision to do without tritium monitoring that was taken after the set up of the emission monitoring instrumentation, is considered appropriate in view of the tritium inventory and the expected low specific discharge of the facility. The submitted WAK program on environmental monitoring is suited to monitoring the possible effects of the VEK operation, as well.

The release regulations available for the WAK are sufficient for the operation of the VEK. However, it is recommended to document all radiologically relevant data in such a way that they can be fallen back upon when the VEK will be dismantled later on.

This Statement has been published in volume 67 of the series “Veröffentlichungen der Strahlenschutzkommission" (Publications of the Commission on Radiological Protection).