Building of the new low level radioactive-waste transporting ship

Building of the new LLW transporting ship1. Purpose NFT owns the LLW transporting ship, Seiei-maru, which has transported about 300 thousand LLW drums for 27 years with excellent safety records. Since it will retire from service by September 2019, a new LLW ship has been started building from April 2016 as a successor of Seiei-maru and the construction of it will be completed in March 2019. In this paper, the NFT’ contrivances of construction and examination will be introduced in building of LLW ship. 2. Contrivance of construction and examination Reuse of CL from nuclear plantIn Japan, there are examples that CL from nuclear plant was reused as a bench or fence in some nuclear power plant site, but it has never been reused as a general industry. For our ships, there is a counterweight to reduce the inclination when using the crane of the ship. And using of CL about 50 ton was decided for counterweight, which resulted in contribution to reusing of CL the recycling-based society.Shielding constructionConcrete are adopted as a shielding material for the ship to satisfy the regulations for the carriage and storage of dangerous goods in ship. In order to ensure shielding performance, concrete should be uniformly constructed without defects such as gaps and holes inside. The filling situation inside the concrete after curing is not confirmed directly, therefore a mockup test to make the same size of a concrete section of the ship was conducted in order to confirm the validity of the construction method. To confirm the full satisfaction of the regulation, it took 16 months to make the shielding construction by the qualified method and to perform gamma(γ) rays shielding test. 3. A specifications of new LLW transport shipBased on lessons learned from the tsunami attack by the Great East Japan Earthquake and operational knowledge, NFT has no doubt that our new ship has the highest level of safety. Especially, NFT introduced the importance of emergency evacuation at the Earthquake, to secure the redundancy by reviews of pedal locomotion, enlarging side thruster, Joystick manoeuvring is possible.