1. NAME AND TITLE

REFREP: A Near-Field Model For A Spent Fuel Repository.

2. CONTRIBUTOR

Technical Research Center Of Helsinki, Finland, through NEA Data Bank, Gif-sur-Yvette, Cedex, France.

3. CODING LANGUAGE AND COMPUTER

Fortran 77; VAX 8810.

4. NATURE OF PROBLEM SOLVED

REFREP calculates mass flows of corroding species and radionuclides (actinides) in the near-field of a canister in a crystalline rock repository.

5. METHOD OF SOLUTION

Inventories and release rates are calculated as a function of time for a given initial inventory. Species are assumed to diffuse through the backfill and to be carried by the groundwater flowing in rock fissures around the disposal hole. Congruent as well as non-congruent release from the fuel matrix can be considered. Release rates from canisters can be summed up using different probability distributions for canister breaching times.

REFREP is divided into different subroutines performing specific tasks. UPDATE allows for the viewing and updating of the data files. CORRFLUX calculates the breaching times of canisters. INVENT calculates actinide inventories from decay chains. ELEMENT calculates elemental inventories of actinides. CONGRUENT calculates nuclide release rates according to congruent release. SENSIT performs sensitivity analysis of one variable. PROBREL sums release rates from individual canisters according to given probability distributions of canister breaching times. DATAOUT forms a compact data file including all input values.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

REFREP is highly interactive. Run times depend on the complexity of the problems; the sample input took only a few seconds on a VAX 8810 at NEA Data Bank.

8. COMPUTER HARDWARE REQUIREMENTS

REFREP runs on the VAX 8810.

9. COMPUTER SOFTWARE REQUIREMENTS

The code was written in Fortran 77. On the VAX 8810, the compiler used was VAX Fortran under the VMS version 5.1 operating system.

10. REFERENCE

a. Included in the documentation:

Aimo Hautojarvi and Timo Vieno. REFREP: A Near-Field Model For A Spent Fuel Repository, YJT-88-07, Helsinki, Finland, May 1988.

Aimo Hautojarvi. ``Simplified Modeling Of Mass Transport In A Fissured Rock-Clay Buffer System,'' Workshop On Artificial Clay Barriers For High Level Radioactive Waste Repositories, Lund, Sweden, October 5-7, 1988.

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one DS/DD (360 K) 5.25 inch diskette.

12. DATE OF ABSTRACT

December 1990.