1. NAME AND TITLE OF DATA LIBRARY

PUDK-82: Measured Results of Delayed Beta- and Gamma-Ray Spectra Due to Thermal-Neutron Fission of Pu₂₃₉ and Pu₂₄₁.

2. NAME AND TITLE OF DATA RETRIEVAL PROGRAMS

No retrieval program is in the package.

3. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

4. HISTORICAL BACKGROUND AND INFORMATION

In the event of a hypothetical loss-of-coolant-accident (LOCA) in a light-water reactor, the fissioning process would cease. A few seconds later, the major source of heat in the fuel rod would be due to the beta and gamma rays from the decay of the accumulated fission products which are produced in the course of the reactor operation.

Energy-release from decay of fission products created by thermal-neutron fission of ²³⁵U has been studied experimentally very thoroughly. A data base is required for all fission products which includes rates-of-production and energies and branching ratios of the decay products. Compilations of such data exist; however, especially for short-lived fission products, the data are incomplete or include substantial components from theoretical estimation.

5. APPLICATION OF THE DATA

Thus far, all of the experimental efforts have been directed at understanding energy-release rates as a function of time following thermal-neutron fission of ²³⁵U. Calculations have been the basis for using the "conservative" procedure in an accident analysis of assuming that all energy-release rates are due to ²³⁵U fission. This procedure results in overestimates of the fission-product energy-release rates. Therefore, it is felt that accurate experimental data for energy-release rates following fission will provide a more reliable and accurate basis for accident analysis as well as further test the validity of the summation calculations.

6. SOURCE AND SCOPE OF DATA

The purpose of experiments was to measure the total beta and gamma energy-release rate from fission product decay following thermal neutron fission of the fuel element ²³⁹Pu. One set of data was obtained for gamma energy-release using a gamma-ray detector; another set for beta decay energy-release using a beta-ray detector. The Oak Ridge Research Reactor (ORR) was used to provide the thermal neutrons.

Small samples of ²³⁹Pu were irradiated for short periods of time and were rapidly recovered following irradiation. Data were obtained by detecting and measuring individual events for several irradiation times, waiting times following the end of the irradiation, counting times starting at the end of the waiting time, and particle energies. The resulting energy spectra were integrated over particle energy to obtain the energy release for each component for every combination of irradiation, waiting, and counting times.

7. DISCUSSION OF THE DATA RETRIEVAL PROGRAM

Not applicable.

8. DATA FORMAT AND COMPUTER

EBCDIC card images; IBM 360/370.9.

9. TYPICAL RUNNING TIME

Not applicable.

10. REFERENCES

J. K. Dickens, J. F. Emery, T. A. Love, J. W. McConnell, K. J. Northcutt, R. W. Peelle, and H. Weaver, "Fission-Product Energy Release for Times Following Thermal-Neutron Fission of ²³⁹Pu Between 2 and 14000 Seconds," ORNL/NUREG-34 (April 1978).

J. K. Dickens, J. F. Emery, T. A. Love, J. W. McConnell, K. J. Northcutt, R. W. Peelle, and H. Weaver, "Fission-Product Energy Release for Times Following Thermal-Neutron Fission of ²⁴¹Pu Between 2 and 14000 Seconds," ORNL/NUREG-47, NUREG/CR-0171 (August 1978).

11. CONTENTS OF LIBRARY

Included are the referenced documents and one (1.2MB) DOS diskette which contains the beta-ray and gamma-ray spectra, edit programs for gamma and beta spectra, and beta-ray and gamma-ray spectra output.

12. DATE OF ABSTRACT

March 1985.