Dismantling method of fuel cycle facilities obtained by dismantling of the JRTF

再処理特別研究棟の解体により得られた核燃料施設における解体工法

金山 文彦 

Kanayama, Fumihiko

原子力に関する研究・開発の進展に伴い、老朽化した原子力施設を解体する機会が多くなる。原子力機構は原子炉施設の解体については、JPDRを用いての実規模の研究開発が行われているが、核燃料使用施設についてはそれらの経験を持ち合わせていなかった。汚染核種,機器がセル内に配置されていること等により、核燃料使用施設における解体では、原子炉施設と違う解体工法が必要であると考えられた。そのため、再処理特別研究棟を用いて、廃止措置プロジェクトが進められることとなった。再処理特別研究棟にはコンクリートセル内に再処理試験に用いた機器や廃液の貯蔵に用いられた機器が存在しており、それらの一部の撤去が行われている。これらの解体対象のうち、セル内廃液貯槽及び壁貫通配管について、適切な解体工法を選択するために、2種類の解体工法が試された。これらの解体より得られた作業データを比較することにより、それぞれの工法の長所及び短所を紹介するとともに、これらの解体工法を選択するに適した条件を紹介する。

With the development of researches and investigations for atomic energy in Japan, various nuclear institutes have been built since 1960s. Today, large numbers of nuclear institutes became old and should be dismantled near future. Necessities for dismantling technology for atomic institutes became large. To dismantle atomic institutes, many cost and time are required. By choosing appropriate method, the cost and time for dismantling can be decreased. To choose appropriate method, it is important to collect the dismantling data of each kind of method, and understand advantages and disadvantages of each dismantling method accurately. To plan the nuclear facility which can be dismantled easily, and to promote setting up and dismantling efficiently, it is important to understand advantages and disadvantages of each dismantling method accurately, too. In JAEA, JPDR was dismantled to get experience of dismantling method of nuclear reactor. But, JAEA did not have experience of fuel cycle facility. Dismantling cost of fuel cycle facilities are more than that of nuclear facilities due to the contamination by TRU nuclide in fuel cycle facilities, In this report, to find appropriate method for dismantling fuel cycle facility, we dismantled liquid waste storage tank and wall-penetrating pipings in JRTF, which was one of the reprocessing facilities in JAEA. Number of man-days and occupational dose required were estimated to reveal advantages and disadvantages of two dismantling methods in each component. Moreover, appropriate conditions to select these dismantling methods are introduced.