The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 31, 1978
Filed:
Dec. 13, 1976
Masataka Aoki, Hitachi, JA;
Hitachi, Ltd., , JA;
Abstract
A pressure vessel of a nuclear reactor is bodily enclosed by an inner layer made of a heat insulating material and an outer layer made of a radiation shielding material, and a nozzle joined by welding to the pressure vessel and a pipe joined by welding to the nozzle projected outwardly from the pressure vessel to extend through openings formed in the two layers. A removable heat insulator detachably attached to an edge of the inner layer defining the opening is disposed in a manner to surround the nozzle. A shielding frame is secured to walls defining the opening in the outer layer, to provide a manhole through which the nozzle and the pipe extend. A plurality of radiation shielding blocks are hingedly supported by an outer end of the shielding frame which is remote from the pressure vessel, while a plurality of radiation shielding plates are hingedly supported by an inner end of the shielding frame which is near to the pressure vessel. When the nuclear reactor is in operation, the radiation shielding blocks are kept in a closed position to plug the manhole, while the radiation shielding plates are kept in an open position. If the nuclear reactor is shut down and inspection of the welds is performed, the radiation shielding blocks are opened, the heat insulator is temporarily removed from its position and some of the radiation shielding plates are closed whereby an open space between the nozzle and pipe and the shielding frame can be closed to avoid exposure of the whole-body of the inspector to radiation.