RRFM 2009 Transactions - European Nuclear Society

LEU FUEL DISPOSITION AT WWR-M REACTOR AFTER
IRRADIATION TEST
KONOPLEV K.A., ORLOV S.P. AND ZAKHAROV A.S.
Physics and Technology of Reactors Department
Petersburg Nuclear Physics Institute
PNPI, 188300, Gatchina, Russia
ABSTRACT
This presentation concern the disposition of two irradiated pin-type experimental
fuel assemblies , which were tested in PNPI WWR-M reactor in support of
demonstration of high-density fuel.
The non-standard design of experimental fuel assemblies As requires a revision of
procedures for storage and further utilization. One way is preparation for
transportation to recycling plant together with standard fuel assemblies after
cooling in wet spent fuel storage. Alternative is reloading to long-term spent fuel
storage.
Introduction
The two pin-type experimental fuel assemblies were tested in PNPI WWR-M reactor in
support of demonstration of high-density fuel for research reactors [1].
Pin fuel is considered as alternative variant for replacing of standard fuel based on tube fuel
elements. In view of conversion purpose serious limitation of thin-wall tubes is small volume
of fuel meat. Pin fuel technology provides additional volume for fuel. At the same time pins
demand fuel assembly casing. It means that small core grid pitch result in the loss of power
density.
The experimental fuel assemblies with LEU fuel were delivered by VNIINM [2]. One fuel
assembly contains fuel elements based on UO 2 and other - UMo. Both types of fuel elements
have an aluminium matrix and cladding. Each of fuel assemblies contains 37 pin elements
(Fig.1) inside of hexagonal aluminium assembly casing .
The volumetric contents of fission fraction in fuel elements in both cases are approximately
identical (Table 1).
No
Fuel
composition
Average
uranium-235
load per FE,
g
Uranium
concentration
in fuel, g/ cm 3
Length of
fuel
meat,
mm
Volume
share of fuel
component,
%
1 (U-Mo) + Al 2.54 5.3 500 33.9
2 UO 2 + Al 1.30 2.7 500 31.0
Table 1. Features of fuel
Features of fuel assemblies are presented in Table 2.
406 of 455