Development of the flow control irradiation facility for JOYO

Soroi, Masatoshi; Miyakawa, Shunichi

This report describes the present situation and problems with the development of the flow control irradiation facility (FLORA). The purpose of FLORA is to run the cladding breach (RTCB) irradiation test under loss of flow conditions in the experimental fast reactor "JOYO". FLORA is a facility like FPTF (Fuel Performance Test Facility) plus BFTF (Breached Fuel Test Facility) in EBR-II, USA. The technical feature of FLORA is its annular linear induction pump (A-LIP), which was developed in response to a need identified through the experiences in the mechanical flow control of FPTF. We have already designed the basic system facility of FLORA for the JOYO MK-II core. However, to put FLORA to practical use in the future, we have to confirm the stability of the JOYO MK-III core condition, solve problems and improve the design. The main results and problems of the development of FLORA are as follows; (1)The results of the development: (a)The neutron detector in FLORA can detect the delayed neutron which is emitted from failed fuel. (b)Out-of-pile A-LIP tests in sodium conditions has been completed. (The length of the tested A-LIP is half the actual size.) Out-of-pile test results showed that the A-LIP achieved a 300/min flow rate and 265kPa pressure in 550C sodium. This pump performance satisfied the FLORA requirements. (c)By controlling the sodium flow rate from 40 to 100% using the A-LIP, we can control the fuel cladding temperature satisfactorily. (2)The problems: (a)In the development of the process detector, it is necessary to miniaturize the neutron detector and test the effect of neutron irradiation and high temperatures on the permanent magnet in the flow meter. (b)The problem which is left about A-LIP is its influence on neutron irradiation. For this purpose, we have to irradiate a small size A-LIP and test its characteristics and electric isolation. (c)To get more accurate results concerning the efficiency of the A-LIP, we have to ...