Patent Number: 047626704
Section: summary

FIELD OF THE INVENTION AND RELATED ART STATEMENT The present invention relates to a cleaning apparatus for washing and disassembling an atomic reactor control rod driving means (hereinafter abbreviated as "CRD") and, more particularly, to a cleaning apparatus for washing and disassembling a CRD having a multitubular structure. A conventional CRD maintenance and inspection operation is roughly classified into the following two operations. (1) CRD replacing operation (2) CRD disassembling, washing and assembling operations These operations (1) and (2) are manually performed and have the following drawbacks. That is, among all the maintenance/inspection operations for a boiling water reactor, they are performed under the worst operation conditions, need the longest operation period of time and the largest number of workmen, and expose the workmen to radiation in the largest amount. Even at the present stage, however, the "CRD replacing operation" has already been greatly improved by applying a remotely controlled CRD replacing means. Thus, a subsequent urgent improvement has now been demanded in the "CRD disassembling, washing and assembling operations". In this regard, an automatic washing apparatus has been proposed in Japanese Patent Unexamined Publication No. 56-89097. The cleaning apparatus disclosed in the Publication includes a water tub, a filter washing nozzle unit for washing the filter of the CRD, a strainer washing nozzle unit, a truck, clamp unit mounted on the truck, grapple units mounted on the water tub, an outer-surface washing nozzle and an inner-surface washing nozzle. However, the apparatus is not sufficiently automatic. Japanese Patent Unexamined Publication No. 58-33198 discloses an inner-surface washing means including a lance provided with a nozzle at the tip end thereof, Japanese Patent Unexamined Publication No. 58-60288 discloses a truck for loading a CRD including clamp units, Japanese Patent Unexamined Publication No. 58-61495 discloses a grapple unit mounted on the water tub and Japanese Patent Unexamined Publication No. 58-62587 discloses a filter washing nozzle unit to spray washing unit onto the filter of CRD. The present invention is directed to improve the apparatus by taking into the above elements. Another cleaning apparatus has been proposed in Japanese Utility-Model Unexamined Publication No. 58-127396. The apparatus comprises a water tub for receiving a CRD, a filter washing device disposed in the water tub, a parts-handling device moving the CRD in longitudinal direction thereof while rotating the CRD in circumferential direction and disassembling the CRD and a conveyor moving the parts handling device above the water tub in longitudinal direction thereof. OBJECT AND SUMMARY OF THE INVENTION The object of the present invention is to shorten the operation time period, reduce the operation labor used and reduce the amount of the radiation exposure by making most of the CRD disassembling and washing operation automatic. To attain the above object, according to the present invention, there is provided a CRD cleaning apparatus comprising a water tub for washing a CRD, rails laid within the water tub, a truck for loading the CRD, which is installed on the rails, a CRD clamp unit mounted on the truck, which has means for rotating the CRD in the circumferential direction as well as for clamping the CRD, a CRD disassembling and assembling graple unit installed within the water tub, which is intended to clamp the CRD and move the same sideways, an outer-surface washing nozzle for washing an outer tube surface and strainer of the CRD, a lance installed within the water tub, which is insertable into the tubes of the CRD and which is equipped with a nozzle assembly intended to spray the washing water onto the inner surface of the tubes, a filter washing nozzle unit installed within the water tub, which is intended to spray the washing water onto a cylindrical filter of the CRD, a washing-water circulating pipe which is connected to the water tub, and a filter unit provided on a portion of the pipe, which is intended to filter the washing water.