A brief history of nuclear energy technologies Barbara Rauter Daniela Wachter

 Definitions and history of fission and fusion  Important components of a nuclear fission reactor  Overview on nuclear fission reactors  Nuclear fusion reactors  Accidents at nuclear power plants

 fuel  moderator  control rods  coolant  pressure vessel or pressure tubes  steam generator  containment Scheme of a nuclear fission reactor (adapted from Lancaster University, 2011)

Nuclear reactor types in use worldwide (as of 1 January, 2003 (adapted from OECD Nuclear Energy Agency, 2005: 17)

The evolution of nuclear power (Böck, 2009b)

 Besides problems such as – mining of radioactive material (uranium ore) – production of radioactive waste, which should be stored safely for thousands of years is prone to proliferation  Accidents result in the most severe consequences for people and the environment  Only advantage of some accidents: Triggered technical/safety improvements of succeeding reactor models

 INES = International Nuclear and Radiological Event Scale  Tool to rate the safety significance of civil (non- military) nuclear and radiological events  Applies to any event associated with transport, storage and use of radioactive substances: – operations at nuclear facilities – industrial and medical use of radiation sources – loss or theft of radioactive material

INES Scale (IAEA, 2008: 1)

 Three areas of impacts are considered: – Impacts on people and the environment – Effects on radiological barriers and control inside an installation – Impairment of safety measures (Defence-in-Depth)  Examples: – Chernobyl: Level 7 in the category “people and the environment” – Three Mile Island: Level 5 rating in the area “radiological barriers and control” – Fukushima: Successively upgrading: First provisional rated at Level 4 by the Japanese Nuclear Safety Authority “NISA” Later upgraded to Level 5 On April 12, 2011 NISA graded the incidents up to the highest level, 7