DETERMINATION OF THE 6.13 MEV PHOTON-EMISSION FROM THE PU(ALPHA,N)(13) SOURCE AND HALF-LIFE OF N-16

To control the safe operation of the nuclear power plant Temelin in th e Czech Republic an apparatus registering the presence of N-16 is inst alled in the secondary circuit. On the basis of N-16 activity measurem ent any eventual leakage from the primary into the secondary circuit i s determined using a calculational model. A critical factor is the cor rect calculation of the detector efficiency for 6.13 MeV photons. The correctness of the calculations was verified by comparing calculated a nd measured efficiencies for photons emitted by Cs-137, (CO)-C-60, Na- 24 and Th-232 sources Of known activities and for 6.13 MeV photons pro duced due to the C-13(alpha,n)O-16 reaction in a Pu(alpha,n)C-13 neutr on source with a certified emission rate for 6.13 MeV photons. Both th e calculations and measurements were done in a very simple geometrical arrangement for NaI(T1), EGO and HPGe detectors by means of various M onte Carlo codes. The difference between the calculated and measured v alues was used to derive the estimated uncertainty of the 6.13 MeV pho ton emission. The half life of N-16 was checked experimentally because of a large scatter of data found in literature.