Induced nuclear reactions: processes – systems – and elements – Handling of fission reactor component structure within... – Storage container systems for new and/or irradiated core...
Reexamination Certificate
2001-10-25
2004-05-25
Carone, Michael J. (Department: 3641)
Induced nuclear reactions: processes, systems, and elements
Handling of fission reactor component structure within...
Storage container systems for new and/or irradiated core...
C376S335000, C376S327000
Reexamination Certificate
active
06741669
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to spent nuclear fuel storage and more particularly to systems and methods for absorbing neutrons in a nuclear fuel storage rack.
BACKGROUND OF THE INVENTION
Nuclear power plants store their spent nuclear fuel in spent fuel storage racks located in on site storage pools. Such racks may be, for example, a Flux Trap Nuclear Fuel Storage Rack
10
as depicted in
FIG. 1
or an Eggcrate Nuclear Fuel Storage Rack
100
as depicted in FIG.
2
. These racks include neutron absorber material
20
(
FIGS. 1-2
and
17
-
18
) to control the re-activity state of the fuel/rack system which is located between a stainless steel inner cell wall
7
and a stainless steel wrapper
9
. Specifically, such absorbers are utilized to neutronically decouple adjacent fuel cell assemblies by maintaining a subcritical condition. In a flux trap storage rack (FIG.
1
), two plates of absorber material
20
separate each storage cell. For example, storage cell
30
and storage cell
35
are separated by plates
32
and
33
. In an eggcrate system (FIG.
2
), one plate of absorber material separates each storage cell. For example, cell
50
and cell
60
are separated by a plate
55
.
This absorber material may be a boron bearing compound in a metal or polymer matrix which may degrade over time as it absorbs neutrons from the spent fuel. For example, the absorber material may be formed of a polymer matrix containing boron carbide (e.g., a BORAFLEX type polymer) and the absorber material may degrade and decrease over a period of several years. Also, charge enrichments for reload fuel for nuclear reactors are generally increasing relative to previous change enrichments and can be as high as 5.0 w/o U-235. The degradation of the absorber material and the use of higher enrichments require replacement of the spent fuel storage racks with racks containing additional absorber material or the insertion of additional absorber material into existing spent nuclear fuel storage racks to control the re-activity state of the fuel/rack system.
Thus, there is a need for a systems and methods for absorbing neutrons in spent nuclear fuel storage racks and particularly systems and methods for restoring neutron absorbing material into spent nuclear fuel storage racks.
SUMMARY OF THE INVENTION
The present invention provides, in a first aspect, a neutron absorber system for a nuclear fuel storage rack. The system includes a neutron absorber, which is adapted to attach to a plurality of cell walls of a cell of the nuclear fuel storage rack. The neutron absorber is adapted to elastically deform to cause it to be attached to the plurality of cell walls.
The present invention provides, in a second aspect, a method of inserting a neutron absorber into a nuclear fuel storage rack. The method includes applying at least one stress to the neutron absorber to cause the absorber to deform and releasing the stress to cause the neutron absorber to attach to the plurality of cell walls of a cell of the nuclear fuel storage rack.
The present invention provides, in a third aspect, a system for inserting a neutron absorber into a nuclear fuel storage rack. The system includes means for applying at least one stress to the neutron absorber wherein the neutron absorber is adapted to elastically deform. The system further includes means for releasing the at least one stress to cause the neutron absorber to attach to the plurality of cell walls of a cell of the nuclear fuel storage rack.
REFERENCES:
patent: 4218622 (1980-08-01), McMurtry et al.
patent: 4225467 (1980-09-01), McMurtry et al.
patent: 4292528 (1981-09-01), Shaffer et al.
patent: 4313973 (1982-02-01), McMurtry et al.
patent: 4581201 (1986-04-01), Haggstrom et al.
patent: 4605440 (1986-08-01), Halverson et al.
patent: 4788029 (1988-11-01), Kerjean
patent: 4820472 (1989-04-01), Machado et al.
patent: 4827139 (1989-05-01), Wells et al.
patent: 4900505 (1990-02-01), Machado et al.
patent: 4960560 (1990-10-01), Machado et al.
patent: 5198183 (1993-03-01), Newman
patent: 5245641 (1993-09-01), Machado et al.
patent: 5361281 (1994-11-01), Porowski
patent: 5479463 (1995-12-01), Roberts
patent: 5579274 (1996-11-01), Van Buskirk et al.
patent: 5629964 (1997-05-01), Roberts
patent: 5786611 (1998-07-01), Quapp et al.
patent: 5841825 (1998-11-01), Roberts
patent: 5848111 (1998-12-01), Wells et al.
patent: 5905770 (1999-05-01), Wasinger
patent: 5909475 (1999-06-01), Wells et al.
patent: 5965829 (1999-10-01), Haynes et al.
patent: 6061414 (2000-05-01), Kopecky et al.
patent: 6166390 (2000-12-01), Quapp et al.
patent: 2-129598 (1990-05-01), None
Cardona, Esq. Victor A.
Carone Michael J.
Heslin Rothenberg Farley & & Mesiti P.C.
Palabrica Rick
LandOfFree
Neutron absorber systems and method for absorbing neutrons does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Neutron absorber systems and method for absorbing neutrons, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Neutron absorber systems and method for absorbing neutrons will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3264141