搜尋結果
Five are considered to be nuclear-weapon states ( NWS) under the terms of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). In order of acquisition of nuclear weapons, these are the United States, Russia (the successor of the former Soviet Union ), the United Kingdom, France, and China. Of these, the three NATO members, the United ...
1989 Tiananmen Square protests and massacre. / 39.90333°N 116.39167°E / 39.90333; 116.39167. The Tiananmen Square protests, known in China as the June Fourth Incident, [1] [2] [a] were student-led demonstrations held in Tiananmen Square, Beijing, China, lasting from 15 April to 4 June 1989. After weeks of unsuccessful attempts between ...
The YES stroke alphabetical order, also called YES stroke-order sorting, briefly YES order or YES sorting, is a Chinese character sorting method based on a stroke alphabet and stroke orders. It is a simplified stroke-based sorting method free of stroke counting and grouping. [1] [2] [3] YES order has been applied to the indexing of Xinhua ...
- Causes
- Light-Water Reactors
- Other Reactor Types
- Soviet Union–Designed Reactors
- Effects
- Reactor Design
- China Syndrome
- See Also
- External Links
Nuclear power plants generate electricity by heating fluid via a nuclear reaction to run a generator. If the heat from that reaction is not removed adequately, the fuel assemblies in a reactor core can melt. A core damage incident can occur even after a reactor is shut down because the fuel continues to produce decay heat. A core damage accident is...
Before the core of a light-water nuclear reactorcan be damaged, two precursor events must have already occurred: 1. A limiting fault (or a set of compounded emergency conditions) that leads to the failure of heat removal within the core (the loss of cooling). Low water level uncovers the core, allowing it to heat up. 2. Failure of the emergency cor...
Other types of reactors have different capabilities and safety profiles than the LWR does. Advanced varieties of several of these reactors have the potential to be inherently safe.
RBMKs
Soviet-designed RBMK reactors (Reaktor Bolshoy Moshchnosti Kanalnyy), found only in Russia and other post-Soviet states and now shut down everywhere except Russia, do not have containment buildings, are naturally unstable (tending to dangerous power fluctuations), and have emergency cooling systems (ECCS) considered grossly inadequate by Western safety standards. The reactor involved in the Chernobyl disasterwas an RBMK. RBMK emergency core cooling systems only have one division and little re...
MKER
The MKERis a modern Russian-engineered channel type reactor that is a distant descendant of the RBMK, designed to optimize the benefits and fix the serious flaws of the original. Several unique features of the MKER's design make it a credible and interesting option. The reactor remains online during refueling, ensuring outages only occasionally for maintenance, with uptime up to 97-99%. The moderator design allows the use of less-enriched fuels, with a high burnup rate. Neutronics characteris...
VVER
The VVERis a pressurized light-water reactor that is far more stable and safe than the RBMK. This is because it uses light water as a moderator (rather than graphite), has well-understood operating characteristics, and has a negative void coefficient of reactivity. In addition, some have been built with more than marginal containments, some have quality ECCS systems, and some have been upgraded to international standards of control and instrumentation. Present generations of VVERs (starting f...
The effects of a nuclear meltdown depend on the safety features designed into a reactor. A modern reactor is designed both to make a meltdown unlikely, and to contain one should it occur. In a modern reactor, a nuclear meltdown, whether partial or total, should be contained inside the reactor's containment structure. Thus (assuming that no other ma...
Although pressurized water reactors are more susceptible to nuclear meltdown in the absence of active safety measures, this is not a universal feature of civilian nuclear reactors. Much of the research in civilian nuclear reactors is for designs with passive nuclear safety features that may be less susceptible to meltdown, even if all emergency sys...
The China syndrome (loss-of-coolant accident) is a nuclear reactor operations accident characterized by the severe meltdown of the core components of the reactor, which then burn through the containment vessel and the housing building, then (figuratively) through the crust and body of the Earth until reaching the opposite end, presumed to be in "Ch...
Annotated bibliography on civilian nuclear accidents from the Alsos Digital Library for Nuclear IssuesTaiwan,[II][k] officially the Republic of China (ROC),[I][l] is a country[27] in East Asia.[o] It is located at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the northeast, and the Philippines to the south. The territories controlled by the ...
Testing and deployment Nuclear weapons have only twice been used in warfare, both times by the United States against Japan at the end of World War II.On August 6, 1945, the United States Army Air Forces (USAAF) detonated a uranium gun-type fission bomb nicknamed "Little Boy" over the Japanese city of Hiroshima; three days later, on August 9, the USAAF detonated a plutonium implosion-type ...
Excess steam from the drywell enters the wetwell water pool via downcomer pipes. SFP: spent fuel pool area. SCSW: secondary concrete shield wall. The Fukushima nuclear accident was a major nuclear accident at the Fukushima Daiichi nuclear power plant in Ōkuma, Fukushima, Japan which began on March 11, 2011.
