From missing seismic devices to insufficient emergency back-up systems, stress tests on Europe\'s nuclear power plants show hundreds of problems requiring billions in new investment, an EU report showed Tuesday. In the report obtained by AFP, the European Commission estimates the cost of improving safety at 134 reactors \"in the order of 10-25 billion euros\" ($13-$32 billion) and wants the upgrades monitored and finalised by 2015. But it demands no plant closures. The report will be officially released by Energy Commissioner Gunther Oettinger on Thursday. The recommendations, to be put to European Union leaders for approval at an October 18-19 summit, are based on stress tests carried out following Japan\'s Fukushima disaster in March 2011. With 111 European reactors located in built-up areas of more than 100,000 people living within 30 kilometres, \"the EU must learn the lessons of Fukushima to further reduce the risk of nuclear incidents in Europe,\" the report says. The 25-page report was drafted with the participation of the 14 EU nations that operate nuclear power plants, as well as Lithuania, Switzerland, Ukraine and Croatia. The tests simulated safety in case of floods, earthquakes and airplane crashes when \"normal safety and cooling functions\" are shut down. A separate study looking at safety in the case of terror attacks is also under way. On the basis of the stress tests, \"practically all nuclear power plants need to undergo improvements as hundreds of technical upgrade measures have been identified,\" it said, lamenting that measures agreed after the accidents at Three Mile Island and Chernobyl \"is still pending in some member states.\" It notably cited the case of 10 reactors where on-site seismic instrumentation has yet to be installed. In some 50 others seismic instruments needed to be upgraded. It also said only four countries currently operate a back-up emergency centre in case the main control room becomes inhabitable in a severe accident.