1. NAME AND TITLE OF DATA LIBRARY

UKFY2: UK Fission Product Yield Library, Version 2.

2. NAME AND TITLE OF DATA RETRIEVAL PROGRAMS

FITFYS and FYSSCAN.

3. CONTRIBUTOR

Winfrith Technology Centre, AEA Technology, UK, University of Birmingham, UK, through the NEA Data Bank, Issy-les-Moulineaux, France.

4. HISTORICAL BACKGROUND AND INFORMATION

Reliable and complete libraries of fission product yields with specified accuracies are needed for many different nuclear calculations, including those on decay heat, dosimetry, burn-up, fuel handling, and safety.

This is the third of four reports devoted to the latest United Kingdom evaluation of fission yields.

5. APPLICATION OF THE DATA

The nuclides that are evaluated in this data library are important for reactor design and operation and for fuel and waste management.

6. SOURCE AND SCOPE OF DATA

UKFY2 is an evaluation of fission product yields derived from the thermal, fast, and 14 MeV neutron-induced fission of the following: 232Th, 233U, 234U, 235U, 236U, 238U, 237Np, 238Np, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, 241Am, 242mAm, 243Am, 243Cm, 245Cm; and from the spontaneous fission of 242Cm, 244Cm, and 252Cf.

7. DISCUSSION OF THE DATA RETRIEVAL PROGRAM

Both of the data retrieval programs were created for PCs using MS Fortran 5.0.

FITFYS generates the covariance matrix for a fission system. FYSSCAN produces optimum values of constraints and repeatedly applies more constraints to the adjustments.

8. DATA FORMAT AND COMPUTER

ASCII card images in ENDF-6 format; IBM-PC.

9. TYPICAL RUNNING TIME

Run times for FITFYS and FYSSCAN on a Northgate 486/66 using the included sample problem varied dependent on the use of the software caching program SMARTDRV. FITFYS ran in approximately 15 seconds with SMARTDRV enabled. Run time was about the same for FITFYS with SMARTDRV disabled (took less than 1 second longer). FYSSCAN ran in 24 minutes 2 seconds using SMARTDRV and ran in 41 minutes 30 seconds without it.

10. REFERENCES

M. F. James, R. W. Mills, D. R. Weaver, "A New Evaluation of Fission Product Yields and the Production of a New Library (UKFY2) of Independent and Cumulative Yields. Part I. Methods and Outline of the Evaluation," AEA-TRS-1015 (April 1991).

M. F. James, R. W. Mills, D. R. Weaver, "A New Evaluation of Fission Product Yields and the Production of a New Library (UKFY2) of Independent and Cumulative Yields. Part II. Tables of Measure and Recommended Fission Yields," AEA-TRS-1018 (April 1991).

M. F. James, R. W. Mills, D. R. Weaver, "A New Evaluation of Fission Product Yields and the Production of a New Library (UKFY2) of Independent and Cumulative Yields. Part III. Tables of Fission Yields with Discrepant or Sparse Data," AEA-TRS-1019 (april 1991).

11. CONTENTS OF LIBRARY

Chain yield data, average cumulative yields, unadjusted chain yields, experimental data base, and the data retrieval programs are transmitted on one DS/HD 5.25-inch (1.2 MB) diskette in DOS compressed format.

12. DATE OF ABSTRACT

September 1993.