While Japanese electric arc furnaces that use ferrous scrap to make steel have radiation detection systems at their plant gates, there is no uniform safety radiation standard for the metal industry and the criteria ranges from 0.3-0.5 microsievert/hour, according to two scrap dealers in Tokyo.
Though some companies have changed the standards since the nuclear disaster following the March 11 quake — either tightening them or easing them, the standards may be changed further in the coming months, various sources added.
Scrap from areas around the stricken Fukushima nuclear power plant has been limited so far as the region moves to restore power, water, road and communication infrastructure, but could increase next month, said one source.
One South Korean steel mill is said to have adopted the standard set by its trade partner in Japan, which is in the 0.3-0.5 microsievert/hour range, two sources said.
Chinese steelmakers, which export scrap from Japan, are likely to adopt this standard, although some mills may suspend purchases from Japan for a while, waiting for the Fukushima nuclear crisis to stabilize, the sources added.
An official at the nonferrous metal department of Japan’s Ministry of Economy, Trade & Industry said the country had no radiation standard for metal and that companies set their own standards to suit their business circumstances.
A national safety standard is only set for farm products in Japan.
Meanwhile, the government has advised industries to have third-party organizations check radiation levels of products, according to an industry association official, but the official declined to confirm this.
Separately, secondary aluminum smelters, steel mills, rolling mills, extruders and other companies handling scrap and metal ingots typically stored outdoors, have also purchased radiation measurement equipment to manage radiation, company sources said.
While radioactive materials continues to be released from Tepco’s stricken Fukushima Daiichi nuclear power plant, three weeks after the deadly quake, the company Monday released radioactive water into the ocean as there is no other alternative to store water used for cooling the reactor facilities onshore.