TITLE: Cask for radioactive material, method of manufacturing such a cask,
module used thereby and method of shielding neutrons.
European Patent Application EP0020948 A2

ABSTRACT:
A cask 21 for radioactive material, such as nuclear reactor fuel or
spent nuclear reactor fuel, includes a plurality of associated walled
internal compartments (31, 33, 35) for containing such radioactive
material, with neutron absorbing material (51, 53, 54) present to
absorb neutrons emitted by the radioactive material, and a plurality of
thermally conductive members, 37, 39, 41, 43) such as longitudinal
copper or aluminum castings, about the compartment and in thermal
contact with the compartment walls (55, 57) and with other such
thermally conductive members and having thermal contact surfaces
between such members extending, preferably radially, from the
compartment walls to external surfaces of the thermally conductive
members, which surfaces are preferably in the form of a cylinder. The
ends of the shipping cask also preferably include a neutron absorber
and a conductive metal covering to dissipate heat released by decay of
the radioactive material. A preferred neutron absorber utilized is
boron carbide, preferably as plasma sprayed with metal powder or as
particles in a matrix of phenolic polymer, and the compartment walls
are preferably of stainless steel, copper or other corrosion resistant
and heat conductive metal or alloy. The invention also relates to
shipping casks, storage casks and other containers for radioactive
materials in which a plurality of internal compartments for such
material, e.g., nuclear reactor fuel rods, are joined together,
preferably in modular construction with surrounding heat conductive
metal members, and the modules are joined together to form a major part
of a finished shipping cask, which is preferably of cylindrical shape.
Also within the invention are methods of safely storing radioactive
materials which emit neutrons, while dissipating the heat thereof, and
of manufacturing the present shipping casks.

INVENTORS:
Shaffer Sr., Peter Thomas Barnum
Gaffney, Michael Francis

APPLICATION NUMBER: EP19800102405
PUBLICATION DATE: 01/07/1981
FILING DATE: 05/02/1980

ASSIGNEE: CARBORUNDUM CO (US)
INTERNATIONAL CLASSES: G21F1/02; G21C19/07; G21F5/012; (IPC1-7): G21F5/00
EUROPEAN CLASSES: G21F5/012

DOMESTIC PATENT REFERENCES:
EP0002227 Neutron absorbing articlem neutron absorbing plate and use of
 said plate as well as method for manufacture of such article.

FOREIGN REFERENCES:
3667540 HEAT REMOVAL SYSTEM FOR NUCLEAR FUEL ASSEMBLIES
2935616 Radiation shielding container
3845315 PACKAGING FOR THE TRANSPORTATION OF RADIOACTIVE MATERIALS
GB1408396A
2727996 Thermal neutron shield and method for making same
3976809 Coating for metal surfaces and method for application

OTHER REFERENCES:
REPORT LA-3570-MS, LOS ALAMOS Scientific Laboratory of the University
of Cali-fornia, December 1965, R.W. Keil et al.: "Feadibility study for
fabrication ofCu-B4 sheet" Page 3, page 19, page 22