MHI, Obayashi develop radiation-shielded seat for machinery operators

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Mitsubishi Heavy Industries Ltd and Obayashi Corp have jointly developed a “radiation-shielded seat” that suppresses radiation exposures of industrial vehicle operators working in radiation-contaminated areas.

The seat incorporates body armor-like radiation shielding developed by combining MHI’s radiation shielding technology based on development and production of special vehicles, and Obayashi’s decontamination experience, with a target of suppressing radiation exposure of operators by 50%.

MHI will begin marketing the seat in mid-December as an easy-to-use tool to reduce radiation exposure risk of operators engaged in work such as decontamination, debris removal and waste transportation using hydraulic excavators and other industrial vehicles.

The two companies developed the radiation-shielded seat in anticipation of use in various situations, specifically: work performed on the premises of the Fukushima Daiichi nuclear power plant operated by Tokyo Electric Power Company (TEPCO) and decontamination work at nearby high-dose radiation areas; transportation of nuclear waste at interim storage and volume reduction facilities currently under consideration by the Ministry of the Environment; and uses in the event of a severe accident at other nuclear-related facilities. Installation of the new radiation-shielded seat can save cost, time and labor compared with procurement of special radiation-shielded vehicles or conversion of currently operated equipment to radiation-shielded vehicles.

The seat material, including body armor parts (shoulders, arms, chest/abdominal area, thighs, neck), consists mainly of tungsten sheet, which offers excellent radiation shielding capability. Although the seat weighs a considerable 130 kilograms (kg), individual parts weigh less than 20kg and most of their weight is integrally supported by the seat, so the burden on the operator is minimal. In addition, the operator can put on and remove the armor-like parts easily by opening/closing the front like a vest, and each part is adjustable in the front-back and up-down directions. Together these features provide a high rate of radiation shielding while simultaneously minimizing fatigue during continuous work and inconvenience to machine operation from wearing such shielding.