Measurement of high-energy prompt fission -rays from neutron induced fission of U

Makii, Hiroyuki   ; Nishio, Katsuhisa   ; Hirose, Kentaro  ; Orlandi, R.  ; Lguillon, R.; Ogawa, Tatsuhiko   ; Soldner, T.*; Hambsch, F.-J.*; Ache, M.*; Astier, A.*; Czajkowski, S.*; Frost, R.*; Guo, S.*; Kster, U.*; Mathieu, L.*; Otsuki, Tsutomu*; Petrache, C. M.*; Pollitt, A.*; Sekimoto, Shun*; Takamiya, Koichi*; Tsekhanovich, I.*

The Japanese government has a plan to remove the fuel debirs for the full deconstruction of Fukushima I Nuclear Power Plants. The fuel debris must be removed without reaching criticality. However, it is difficult to monitor the fission rate due to the background rays coming from long-lived fission products. We are proposing to develop a system based on the use of the high-energy prompt fission rays, whose energies are high enough to be separated from the background. To design the system, it is essential to know the spectrum of prompt fission rays up to more than 7 MeV for U(). So far, no data are available in the -ray energy range larger than 7 MeV. This prompted us to make a new measurement to extend the -ray spectrum limit to higher energies. The measurement has been carried out at the PF1b cold-neutron beam facility of the Institut Laue-Langevin. In this contribution we will present the results obtained the measurement.