Beta energy release following the thermal neutron induced fission of 233U and 235U

• Published in: Journal of nuclear energy (1967) 1971, Vol.25 (1), p.1-10
• Main Authors: Scobie, J., Scott, R.V., Wilson, H.W.
• Format: Article
• Language: English
• ISSN: 0022-3107; 1878-4410
• DOI: 10.1016/0022-3107(71)90042-6

Measurements have been made of the relative beta energy release rates following the thermal neutron induced fission of 233U and 235U as part of a continuing programme of work in this general field. The results are presented as a ratio of the 235U release rate to that of 233U as a function of time following an irradiation of 10 4 sec duration. Calculations of the above ratio have been performed using calculated independent yields and the decay schemes of the various nuclides. The calculation is limited to times greater than 60 sec after irradiation because of lack of knowledge of the decay schemes, and half-lives, of the short lived fission products. The absolute beta energy release rates are given for the two cases and compared, in the case of 235U with some previous calculations and experiments. Theory and experiment agree qualitatively in that the 235U to 233U ratio is initially greater than unity and decreases with time to reach values less than unity. However, the time found experimentally at which the ratio equals unity is not reproduced in the calculation. Further, both experiment and theory indicate that at long times (> 10 4 sec) after irradiation the ratio increases again to a value greater than unity.