Nuclear Fuel Cycle II PhDr. Tomáš Vlček, Ph.D. International Relations and Energy Security Department of International Relations and European Studies Nuclear Fuel Cycle 4 The Middle Part When and where took the first chain reactions in nuclear reactor place? When and where was the first nuclear reactor connected to the electricity grid? When and where took the first chain reactions in nuclear reactor place? December 20, 1951, at the Experimental Breeder Reactor EBR-I in Arco, Idaho, USA When and where was the first nuclear reactor connected to the electricity grid? June 26, 1954, at Obninsk, Russia, the nuclear power plant APS-1 with a net electrical output of 5 MW World reactor fleet 2017  413 operating reactors  31 countries  50 under construction ◦ 16 in China, 5 in Russia, 7 in India ◦ 4 in S. Korea, 4 in UAE Nuclear power plants Nuclear power plants in commercial operation Reactor type Main Countries Number GWe Fuel Coolant Moderator Pressurised Water Reactor (PWR) US, France, Japan, Russia, China 271 270.4 enriched UO2 water water Boiling Water Reactor (BWR) US, Japan, Sweden 84 81.2 enriched UO2 water water Pressurised Heavy Water Reactor 'CANDU' (PHWR) Canada 48 27.1 natural UO2 heavy water heavy water Gas-cooled Reactor (AGR & Magnox) UK 17 9.6 natural U (metal), enriched UO2 CO2 graphite Light Water Graphite Reactor (RBMK & EGP) Russia 11 + 4 10.4 enriched UO2 water graphite Fast Neutron Reactor (FBR) Russia 1 0.6 PuO2 and UO2 liquid sodium none TOTAL 436 399.3 Nuclear Fission PWR Reactor Loop = Reactor + Main Circulation Pump + Steam Generator Compensators = electric heaters + water showers PWR Reactor Chernobyl NPP, UKR Dukovany NPP, CZE Dukovany NPP Dukovany NPP Zwentendorf NPP, AUT Novovoronezh NPP, RF Obninsk NPP, RF BWR Reactor PHW Reactor  Generally the same structure as PWR  Heavy water (nor radioactive) absorbs less neutrons, thus is able both to moderate nuclear reaction and secure criticality = non-enriched fuel can be used  Fission chain reaction consumes only uranium isotope 235U.  Used fuel contains approximately a quarter of the original value of this isotope, thus still remains enriched to about 1% 235U.  The fuel consists of more than 96% uranium dioxide (UO2) and newly developed plutonium dioxide (PuO2) in an amount of about 1%, and other compounds (3%), while most of the fission products are radioactive isotopes. 33 Back End MOX Fuel  Mixed oxide (MOX) fuel provides almost 5% of the new nuclear fuel used today.  MOX fuel is manufactured from plutonium recovered from used reactor fuel, mixed with depleted uranium.  MOX fuel also provides a means of burning weapons-grade plutonium (from military sources) to produce electricity. MOX Fuel MOX Fuel World mixed oxide fuel fabrication capacities (t/yr) 2009 2020 France, Melox 195 195 Japan, Tokai 10 10 Japan, Rokkasho 0 130 Russia, Mayak, Ozersk 5 5 Russia, Zheleznogorsk 0 60? UK, Sellafield 40 0 Total for LWR 250 400 Fast Neutron Reactors  About 400 reactor-years of operating experience have been accumulated to the end of 2010.  A fast neutron reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons.  Such a reactor needs no neutron moderator, but must use fuel that is relatively rich in fissile material when compared to that required for a thermal reactor.  Fuel consists of U-235, Pu-239 (products of fission with higher radiation) that produce more fast neutrons = waste from Gen II and III reactors is used Fast Neutron Reactors (BN 800) Fast Neutron Reactors Fast Neutron Reactors Back-end of Nuclear Fuel Cycle  In the first phase, the fuel is actively cooled in a pool next to the reactor. After five-ten years they are put into dry containers and passively cooled in interim storages.  Dukovany NPP annually produces less than one container of spent fuel. Temelin NPP annually produces two full containers of used fuel.  The dry interim storage facility is constructed to store fuel for about 80 years.  The second phase, i.e. transport phase, is/will be provided by rail.  The third phase is the underground geological repository Back-end of Nuclear Fuel Cycle Is it safe to swim in the spent fuel pool? Is it safe to swim in the spent fuel pool? https://what-if.xkcd.com/29/ 47 48 Open vs. Closed Cycle Types of waste (1)negligibly hazardous waste (not considered a risk to humans or the environment, e.g. material after the demolition of nuclear power plants) (2)slightly hazardous waste (produced for example in hospitals, pharmacies, some manufacturing processes, and in some parts of the nuclear fuel cycle, this waste does not require casing and can be placed into surface storages) (3)moderately hazardous wastes (e.g. contaminated material after the demolition of the reactor of the NPP, the waste may require cladding and shielding) (4)highly hazardous waste (spent fuel, it is essential to shield and cool it) 49 Surface storage is needed for at least 40-50 years, after which the temperature and the radioactivity drops to a level that is acceptable for underground geological repository with limited or no access of cooling. Geological surveys and technical plans are fairly advanced in Sweden and Finland, which have a defined location. U.S. repository should be built at Yucca Mountain in Nevada, but the decision was postponed. Variants of Storage - Underground - Space - Long-term surface storage