Japan said on Monday that its nuclear reactor \"stress tests\" will be carried out in two stages, prioritising dozens that are now idled, but gave no timeline for when the assessments will start. The centre-left government last week announced the tests, modelled on similar checks in the European Union, in the aftermath of Japan\'s Fukushima Daiichi nuclear crisis, the world\'s worst since Chernobyl 25 years ago. The government of Prime Minister Naoto Kan issued a paper on the \"stress tests\" which said that the idled reactors will be tested, and there will also be more sweeping safety tests of currently running reactors. \"The government will introduce a safety review based on new rules and procedures in addition to the conventional ones,\" Kan\'s top spokesman, Chief Cabinet Secretary Yukio Edano, told a press conference. \"To achieve more confidence about safety, the government will implement the additional checks as an assessment and for assurance so that we can make a judgement on restarting idled reactors.\" Edano said two nuclear industry watchdog bodies the Nuclear and Industrial Safety Agency (NISA) and the Nuclear Safety Commission of Japan will play a major role in carrying out the tests. \"This is all technical procedure, not a decision to be made politically,\" Edano said. \"Technical experts of NISA will draft a test plan and the commission, another group of experts who are independent, will decide if it is feasible.\" Only 19 of Japan\'s 54 reactors have been running since the quake and tsunami four months ago, as local governments and residents have expressed safety concerns, worsening a power crunch in the resource-poor country. The new details on the safety reviews raised market hopes that power shortages will ease earlier and lifted shares of Japanese utilities on Monday, with Tokyo Electric Power Co up 7.29 percent to 441 yen.