1. NAME AND TITLE OF DATA LIBRARY

LUMP: Evaluated Lumped Fission Product Cross Sections for Fast Reactor Analysis--Based on ENDF/B-V Data.

2. NAME AND TITLE OF DATA RETRIEVAL PROGRAMS

No retrieval program is included in the package.

3. CONTRIBUTOR

Argonne National Laboratory, Argonne, Illinois.

4. HISTORICAL BACKGROUND AND INFORMATION

It is standard practice in fast reactor analysis to employ a lumped time-independent cross section set to simulate fission products over a burnup cycle. Various lumping schemes have been used in the past; in order to assess the relative merits of various models it is necessary to consider basic issues such as the dependence on burnup history, fuel composition and neutron spectrum, the impact of data base used, the proper application of the lumped data, the effects of scattering matrix, and the impact of the lumped data on reactor performance.

Recent fast reactor analysis studies at ANL relied on the ENDF/B-III lumped fission product data which are based on the Garrison-Roos model. In an attempt to update this information, an attempt was made to develop a lumped fission product cross section library from the ENDFB-V files. Both one-lump and two-lump models ere investigated in detail.

5. APPLICATION OF THE DATA

The inventory of fission products in a reactor is determined by the operating history of the reactor and the nuclear processes which affect the fission products. The latter include direct yield from fission, several possible modes of radioactive decay, and neutron absorptions. Because there are roughly 100 possible fission product chains consisting of about 800 nuclides, a complete description of all decay and coupling mechanisms which relate the fission product chains is complicated.

6. SOURCE AND SCOPE OF DATA

The EPRI-CINDER-2 computer code was used in this study. Its basic function is to solve the large set of coupled differential equations which describe the temporal concentrations of fission products and actinides in a nuclear reactor. It uses the "linear chain" technique to reduce the complexity of the chain structures. It is suitable for mixed oxide core fast reactor applications. Data are in ENDF/B-V format and the MERGE retrieval program is included to the format of the cross sections.

7. DISCUSSION OF THE DATA RETRIEVAL PROGRAM

Not applicable.

8. DATA FORMAT AND COMPUTER

EBCDIC card images; IBM 360/370.

9. TYPICAL RUNNING TIME

Not applicable.

10. REFERENCES

J. R. Liaw and H. Henryson II, "Evaluation of Lumped Fission Product Cross Sections for Fast Reactor Analysis - An Update," Intra-Laboratory Memo (May 1981).

J. R. Liaw and H. Henryson II, "Evaluation of Lumped Fission Product Cross Sections for Fast Reactor Analysis," FRA-TM-134 (February 1981).

11. CONTENTS OF LIBRARY

Included are the referenced documents and one (1.2MB) DOS diskette which contains the LUMP JCL and sample problem, the MERGER source, the LUMP cross section data, and the LUMP merged cross sections, plus output from the sample problem.

12. DATE OF ABSTRACT

April 1985.