Patent Number: 060875461
Section: description

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, FIG. 1 discloses a nuclear reactor in section showing a cup-shaped reactor vessel 10 and a closure head 12, both filled with low-density cellular concrete 17. The reactor closure head is attached to the reactor vessel by a plurality of threaded studs and nuts 11 and 13 respectively. The reactor vessel contains internal steel components 15 which were used during operation of the reactor primarily to direct the flow of water through the reactor, to support the nuclear fuel, and to guide the control rods as they are removed and reinserted into the fuel region of the reactor. (This invention relates to the reactor shell, reactor closure head, and internal components and does not relate to the nuclear fuel, which is assumed to be removed and stored or shipped to a U.S. government designated location.) Instrumentation and control devices 19 and 21, used during the operation of the reactor, enter the reactor vessel through small penetrations in the top and bottom of the reactor. Reactor coolant piping 18 is welded to the reactor coolant nozzles 14 for operation of the reactor. The instrumentation and control devices and reactor coolant piping have been removed and the reactor vessel has been filled with low-density cellular concrete prior to reactor decommissioning as shown in FIG. 1. The reactor vessel is formed with an enlargement about its annular lip 10A. The lip 10A is formed with vertical threaded stud or bolt holes 13A. In FIG. 2, the reactor vessel 10 and reactor closure head 12 are shown after decommissioning preparatory steps have been completed. A plurality of reactor-closure-head studs 11 formerly in the threaded bolt holes 13A have been replaced with extended-length lifting studs 16. A lifting device 20 and 22 has been connected to the extended-length lifting studs 16. In FIG. 3 the reactor vessel is lifted to a position exposing the reactor coolant nozzle 14 through a notch 50 in a special temporary support ring 27 resting on plant floor 28 above the existing floor. The reactor coolant nozzles 14 are then cut close to the reactor vessel shell to allow the reactor vessel to be lifted into the transportation container shell 24. The steel support ring 27 provides shielding for the workers during nozzle-cutting equipment setup and operation. The steel support ring 27 also provides support for the container shell 24 and reactor vessel 10 and reactor closure head 12. After cutting the reactor coolant nozzles, the lifting process is continued. In FIG. 4 the steel transportation container shell 24 is shown provided with a supplemental steel shielding 26. The reactor vessel 10 and reactor closure head 12 are shown partially lifted into the container shell 24. The container shell is shown provided with inward reactor support lugs 34. In FIG. 5 the nuclear reactor 10, 12 is raised into position inside the transportation package cylinder shell 24. The container is positioned such that the lifting apparatus including the bar 20 and secondary studs 16 do not interfere with the lugs 34. In FIG. 6 the reactor vessel is bolted to the reactor support lugs 34 by securing the final holding studs 44 through the lugs 34 and into bolt holes 13A in the vessel from which the bolts have been removed. Nuts 13 are placed on the studs and tightened. Lifting of the partially complete transportation package defined by the vessel 10, 12 and container shell 24 can be accomplished using the package lifting trunnions 30 which are mounted on the outside of the container shell 24. In FIG. 7 the reactor inward support lugs 34 and package lifting trunnions 30 are shown in plan view, attached to the transportation container shell 24. A clearance space 33 is shown between the vessel 10, 12 and the container shell 24. In FIG. 8 the reactor vessel is shown in vertical sectional view within the transportation container 24. The transportation container upper cover plate 40 or top wall and transportation package lower cover plate or bottom wall 42 are installed on the shell 24 by welding. The clearance space 33 between the reactor vessel and the transportation container 24, 40 and 42 is filled with concrete 43. This stabilizes the reactor vessel within the package transferring the inertia loads of the reactor vessel to the container. This provides additional shielding against ionizing radiation. FIG. 9 provides a sectional view of the welded connection between the package wall 24 and the upper and lower cover plates 40 and 42. The invention is thus a transportation package A (FIG. 8) which completely envelopes a nuclear reactor vessel and head 10, 12 with internal components intact. The invention includes the method of placing the nuclear reactor vessel inside the transportation shell to minimize the exposure of workers to ionizing radiation since the reactor vessel is completely enclosed in the container. It also minimizes the overhead clearance requirements for rigging and lifting the reactor vessel into the package. No part of the reactor vessel is used as a part of the containment boundary of the package. No welding of attachments is performed on the reactor vessel for the purpose of creating the package containment boundary. Variations in the invention are possible. Thus, while the invention has been shown in only one embodiment, it is not so limited but is of a scope defined by the following claim language which may be broadened by an extension of the right to exclude others from making, using or selling the invention as is appropriate under the doctrine of equivalents.