(393KB)
Table 9-1 Relationship between dismantling methods chosen according to facility characteristics and evaluation items
Fig.9-2 Relationship between manpower need and weight of equipment (General equipment (β-γ/U))
Fig.9-3 Comparison of evaluated and actually used labor
We have various types of R&D nuclear facilities which will be eventually decommissioned with their missions completed. To implement decommissioning of these facilities, it is important to make a rational decommissioning plan from a long-term point of view.
The decommissioning cost of the facilities needs to be estimated in advance to develop such a long term plan. In evaluating decommissioning cost, detailed facility information is required in general such as weight of the equipment and contamination distribution in the facility, and the specific procedure of dismantling. However, it will take much time and effort to get such detailed plant information and to determine the procedure. Therefore, a method for evaluating decommissioning cost efficiently, even if the detailed information has not been obtained, needs to be developed. Here, one important issue is how to estimate the manpower required to dismantle the facility and equipment. Once the manpower need is evaluated, it will be possible to evaluate the cost of dismantling operations using unit labor cost, and other cost of decommissioning planning and work management.
Manpower need depends on the dismantling method, which is chosen according to the type of facility. Thus we classified nuclear facilities into reactors, nuclear fuel facilities, research facilities, etc., and made the relationship between the dismantling method and each type of facility (Table 9-1). Manpower need depends on the weight of equipment to be removed, size of the operation area, and the dismantling method. Considering that there is a correlation between weight of equipment or floor area of building and manpower need, we constructed conversion coefficients from weight or area to manpower need by analyzing experienced real data of JAEA operations (dismantling of Japan Power Demonstration Reactor and partial remodeling of Reprocessing Plant). Fig.9-2 shows an example of analysis results of the relationship between manpower needs and weight of equipment. Then, we developed a method for rapidly evaluating decommissioning cost which would be applicable to various types of facilities and dismantling methods.
To verify this method, we applied it to two facilities using unsealed sources, Plutonium Research Building 2 (Pu Bldg.2) and Ceramic Research Building (Ceramic Bldg.). Fig.9-3 shows a comparison of evaluated results and actual data. There was good agreement between them, verifying the accuracy of this method.
<Previous: 9 Development of Decommissioning and Radwaste Treatment Technology | Next: 9-2 >
