Japan Declares Fukushima STABLE!

16 December 2011 "Japan has declared that its tsunami-stricken Fukushima nuclear power plant has reached cold shutdown condition, passing a key milestone in efforts to bring under control the world's worst nuclear accident since Chernobyl 25 years ago. "The reactors have reached a state of cold shutdown condition," Yoshihiko Noda, Japan's prime minister, said at the government's nuclear emergency response meeting on Friday. "Even if unforeseeable incidents happen, the situation is such that radiation levels on the boundary of the plant can now be maintained at a low level," he said. "The government is due to set a clear road map and will do the utmost to decommission the plant," the Japanese PM said. The Fukushima Daiichi plant, 240km northeast of Tokyo, was damaged on March 11 by a devastating earthquake and a 10-metre-high tsunami, which damaged its cooling systems, triggering meltdowns and radiation leaks. Declaring a cold shutdown condition will have repercussions well beyond the plant: it is a government pre-condition before it allows about 80,000 residents evacuated from within a 20km radius of the plant to return home. A cold shutdown condition is when water used to cool nuclear fuel rods remains below its boiling point, preventing the fuel from reheating. One of the chief aims of the plant's operator, Tokyo Electric Power Company (TEPCO), had been to bring the reactors to this stage by the year-end. After months of efforts, the water temperature in all three of the affected reactors fell below boiling point by September, but TEPCO has been cautious of declaring a cold shutdown, saying it had to see if temperatures and the amount of radiation emitted from the plant remained stable. In an interview with Al Jazeera, Imad Khadduri, a nuclear scientist, said: "The Japanese PM’s plans are very formidable and very ambitious and detailed. And one measure of the success of this plan of decontamination can be juxtaposed against the efforts since March when the accident happened. "I am very hopeful that the decontamination will be done in a very meticulous and rigorous manner unlike that of the Chernobyl in Russia nearly 25 years ago," he said. Massive cleanup Khadduri said: "The nuclear power plants, in fact, are large stainless steel eggs under huge pressure, almost 72 times the atmospheric pressure. And by cold shutdown, they mean that the pressure inside the plant has been brought down to the atmospheric level. "In the past more than eight months, they have managed to reduce the temperature of fuel elements to under 95 degrees celsius, which is equal to the atmospheric pressure. "Decommission means: They can remove the top part of the stainless steel egg and take out nuclear fuel elements, store them safely and starting to dissemble the plant and tube them with concrete materials." He further added: "These [highly radioactive nuclear fuels] are stored at radio-established spent fuel storage tanks. These can be stored at nearly 54 other nuclear power stations that have large capacity for spent fuel storage." TEPCO said early in the crisis that it did not plan to entomb the damaged Daiichi reactors in concrete, the option chosen at Ukraine's Chernobyl where reactors caught fire and burned for days. Instead, it favoured the gradual removal of the nuclear fuel for storage elsewhere. The government and TEPCO will aim to begin removing the undamaged nuclear rods from Daiichi's spent fuel pools as early as next year. However, retrieval of fuel that melted down in their reactors may not begin for another decade, with the complete dismantling of the plant expected to take up to 40 years, domestic media reported on Thursday. The enormous cost of the cleanup and compensating the victims of the disaster has drained TEPCO financially. The government may inject about $13bn into the company as early as next summer in a de facto nationalisation, sources told the Reuters news agency last week. Japan also faces a massive cleanup task outside the plant if residents are to be allowed to return home. The environment ministry says about 2,400sq km of land around the plant may need to be decontaminated. The crisis shook the public's faith in nuclear energy and Japan is now reviewing its earlier plan to raise the proportion of electricity generated from nuclear power to 50 per cent by 2030 from 30 per cent in 2010. Living in fear of radiation is part of life for residents both near and far from the plant. Cases of excessive radiation in vegetables, tea, milk, seafood and water have stoked anxiety despite assurances from public officials that the levels detected are not dangerous. Chernobyl's experience shows that anxiety is likely to persist for years to come, with residents living near the former Soviet plant still regularly checking local produce for radiation before consuming them 25 years after the disaster. The announcement may not dramatically improve Noda's support ratings, eroded by his steadfast commitment to a sales tax increase to cope with a public debt burden twice the size of Japan's economy. Noda is also faced with a formidable list of other tasks, such as helping a stagnant economy deal with the yen's rise to historic highs." Taken from http://www.aljazeera.com/news/asia-pacific/2011/12/201112167758128873.html At long last we have waited this moment where Fukushima Daiichi NPP to settle down and be stable.  A joyous news for us!   PS: Okuu-chan is settling down with a cold blanket >XD

Nuclear Powered Aircraft

Today, everybody have heard many nuclear powered vehicles like ships, aircraft carriers, submarines and satellites but how many of you heard of nuclear powered aircraft? Yep... an aircraft. Sounds like a very good idea, having an aircraft that can fly continuously without having to land or refuel for very long periods of time and a great military advantage. But, who want and how to put this much power...
... into an aircraft?

The idea of nuclear-powered aircraft seems crazy with the benefit of hindsight. But for the U.S. Air Force generals of the late 1940s and 1950s, it was the answer to a Cold War dilemma: How can you have a round-the-clock nuclear deterrent when the planes carrying atomic bombs have to stop for fuel every few hours? The fear was that a sneak attack from Soviet bombers could destroy the capacity of the U.S. to retaliate, thus providing an incentive for a first strike.

An atomic-powered bomber would provide the ultimate deterrent, the Air Force Generals believed. With an ability to stay aloft for an extended period, the planes could circle in Arctic airspace waiting for the orders to attack. Crews would live on the bombers much the way that submariners do in nuclear subs, which were just coming online.

US Nuclear Aircraft Project

The only US nuclear aircraft, XB-36H (developed from Convair B-36)
or better known as X-6

NEPA & ANP
In May 1946, the Nuclear Energy for the Propulsion of Aircraft (NEPA) project was started by the United States Air Force. Studies under this program were done until May, 1951 when NEPA was replaced by the Aircraft Nuclear Propulsion (ANP) program. The ANP program included provisions for studying two different types of nuclear-powered jet engines, General Electric's (an aviation company) Direct Air Cycle and Pratt & Whitney's (another aviation company) Indirect Air Cycle. ANP also contained plans for two B-36s to be modified by Convair (also an aviation company) under the MX-1589 project, one of the B-36s was to be used to study shielding requirements for an airborne reactor while the other was to be the X-6. The program was cancelled before the X-6 was completed, however.

The first operation of an aircraft engine on nuclear-power was achieved on January 31, 1956 using a modified General Electric J47 turbojet engine. The Aircraft Nuclear Propulsion program was terminated following the President's annual budget message to Congress in 1961.

General Electric's Direct Air Cycle Engine (the details are classified)

The Oak Ridge National Laboratory conducted research (Aircraft Reactor Experiment) to produce a nuclear powered aircraft. Two General Electric turbofan engines were successfully powered to nearly full thrust using two shielded reactors. The two engines complete with reactor system are currently located at the EBR-1 facility south of the Idaho National Laboratory.

The U.S. designed these engines to be used in a new specially designed nuclear bomber, the WS-125, which was eventually terminated by Eisenhower who cut NEPA and told Congress that there was no urgency for the program. Eisenhower did back a small scale program developing high temperature materials and high performance reactors. That program was terminated early in the Kennedy administration.

Project Pluto
In 1957, the Air Force and the U.S. Atomic Energy Commission contracted with the Lawrence Radiation Laboratory to study the feasibility of applying heat from nuclear reactors to ramjet engines. This research became known as Project Pluto. The engines being developed under this program were intended to power an unmanned cruise missile, called SLAM, for Supersonic Low Altitude Missile. The program succeeded in producing two test engines which were operated on the ground. On May 14, 1961, the world's first nuclear ramjet engine, "Tory-IIA," mounted on a railroad car, roared to life for just a few seconds. On July 1, 1964, seven years and six months after it was born, "Project Pluto" was cancelled.

Soviet Nuclear Aircraft Project
As the Allies main rival during the Cold War, the Soviets have their own nuclear aircraft program too. The Soviet program of developing nuclear aircraft resulted in the experimental Tupolev Tu-119, also known as the Tu-95LAL (LAL-in Russian mean- Flying Nuclear Laboratory). It was based on a Tupolev Tu-95 bomber. It had 4 conventional turboprop engines and an onboard nuclear reactor. The Tu-119 completed 34 research flights. Most of these were made with the reactor shut down.

The Soviet Nuclear Aircraft, Tu-95LAL (classified picture)

The main purpose of the flight phase was examining the effectiveness of the radiation shielding which was one of the main concerns for the engineers. Massive amounts of protection used resulted in radiation levels low enough to consider continuing development. But, as in the US, development never continued past this point. The obvious potential of the ICBM made the expensive program superfluous, and around the mid 1960s it was cancelled. Several other projects reached only design phase.

The Nuclear Reactor On-board Tu-95LAL (again, classified)

Nuclear aircraft is good idea actually... but we have to remember that everything (especially nuclear reactor) are not immune to accidents. Even nuclear power plant with the latest state of the art safety systems is not entirely perfect, let alone a flying "nuclear bomb" under your seat or on top of your head. We already seen many aircraft crashes in the news and sometime a nuclear submarine accidents somewhere in the deep ocean in the last decade, so its possible to assume a nuclear aircraft will suffer the same fate & greater disaster. Thankfully, the nuclear aircraft programs was cancelled since the advent of ICBM (Inter-Continental Ballistic Missile) in the 60s, kinda ironic... is it?

Again, if a nuclear aircraft crashes near your home... O_O!!!

[Video] Three Mile Island, 32 Years Later

32 years later after the incident three mile island.  Three Mile Island, the first nuclear incident in the world, before the most famous Chernobyl.  So dig in!

 

 PS: Okuu-chan almost undergoes meltdown but saved by Rin, her friend, "You're a nuclear core not a heater!"  Now Okuu understands.

[Video] Fukushima Nuclear Crisis, Six Month Later

There's no need to explain, just watch the video.

PS: Regarding TEPCO, I found a gag on the internet (as usual >XD) Okuu-chan apologise and Kappa can just pity at her >XP

Nuclear Reactor Evolution

Developed in 50's and 60's of previous century

• Based on general industry standards
• Only a limited number still in operation

Designed in the 70's

• Based on specific nuclear safety standards
• Safety ensured mainly by active systems
• Safety ensured generally within the design basis envelope
• Extensively used currently in the world

Design in line with the 21st century safety standards

• Design favorable for operation
• Extended reliability within extended lifetime (60 years)
• Minimized core damage probability
• Management of severe accidents (core damage sequences)
• Limited environment impact for all events

Chronological of Nuclear Reactor Development

1940’s

• 1942: World’s first nuclear reactor, Chicago Pile 1 (CP1), achieved criticality.
• 1944: World’s first plutonium production reactor operational in Hanford, USA.

1950’s

• 1951: World’s first nuclear electricity generation with EBR-1 (FBR) in Idaho, USA.
• 1954: World’s first nuclear power submarine, USS Nautilus, launched by the USA & world’s first nuclear power plant(LWGR) operational at Obninskin Russia.
• 1956: First UK nuclear power plant (Magnox), Calder Hall, operational in Sellafield & first nuclear power plant (similar to Magnox) operational in France.
• 1957: First US nuclear power plant (PWR) operational in Shippingport.
• 1959: World’s first nuclear powered merchant ship, NS Savannah, launched in USA.

 1960’s

• 1960: First BWR nuclear power plant operational in Dresden, USA.
  1961: World’s first nuclear powered aircraft carrier, USS Enterprise, launched.
• 1962: First CANDU PHWR nuclear power plant operational in Canada.
• 1965: World’s first nuclear powered satellite, SNAP-10A, launched into orbit by USA.

 1970’s

• 1972: World’s first prototype fast breeder reactor(FBR) power plant, BN-350,
• operational in Shevchenko, Kazakhstan, in former Soviet Union.
• 1979: Three Mile Island II nuclear power plant (PWR) accident in Pennsylvania, USA.

1980’s

• 1986: Chernobyl nuclear power plant (LWGR) accident in Ukraine, former Soviet Union.

1990’s

• 1997: First third generation nuclear power plant(Advanced BWR) operational, in KashiwazakiKariwa, Japan.

How Nuclear Power Works

The nuclear power plant stands on the border between humanity's greatest hopes and its deepest fears for the future.On one hand, atomic energy offers a clean energy alternative that frees us from the shackles of fossil fuel dependence. On the other, it summons images of disaster: quake-ruptured Japanese power plants belching radioactive steam, the dead zone surrounding Chernobyl's concrete sarcophagus.But what happens inside a nuclear power plant to bring such marvel and misery into being? Imagine following a volt of electricity back through the wall socket, all the way through miles of power lines to the nuclear reactor that generated it. You'd encounter the generator that produces the spark and the turbine that turns it. Next, you'd find the jet of steam that turns the turbine and finally the radioactive uranium bundle that heats water into steam.

Welcome to the nuclear reactor core.

The water in the reactor also serves as a coolant for the radioactive material, preventing it from overheating and melting down. In March 2011, viewers around the world became well acquainted with this reality as Japanese citizens fled by the tens of thousands from the area surrounding the Fukushima-Daiichi nuclear facility after the most powerful earthquake on record and the ensuing tsunami inflicted serious damage on the plant and several of its reactor units. Among other events, water drained from the reactor core, which in turn made it impossible to control core temperatures. This resulted in overheating and a partial nuclear meltdown [source: NPR].

As of March 1, 2011, there were 443 operating nuclear power reactors spread across the planet in 47 different countries [source: WNA]. In 2009 alone, atomic energy accounted for 14 percent of the world's electrical production. Break that down to the individual country and the percentage skyrockets as high as 76.2 percent for Lithuania and 75.2 for France [source: NEI]. In the United States, 104 nuclear power plants supply 20 percent of the electricity overall, with some states benefiting more than others.
In this article, we'll look at just how a nuclear reactor functions inside a power plant, as well as the atomic reaction that releases all that crucial heat.

The figure above shows how a Nuclear Power Plant works basically.

In order to turn nuclear fission into electrical energy, nuclear power plant operators have to control the energy given off by the enriched uranium and allow it to heat water into steam.
Enriched uranium typically is formed into inch-long (2.5-centimeter-long) pellets, each with approximately the same diameter as a dime. Next, the pellets are arranged into long rods, and the rods are collected together into bundles. The bundles are submerged in water inside a pressure vessel. The water acts as a coolant. Left to its own devices, the uranium would eventually overheat and melt.
To prevent overheating, control rods made of a material that absorbs neutrons are inserted into the uranium bundle using a mechanism that can raise or lower them. Raising and lowering the control rods allow operators to control the rate of the nuclear reaction. When an operator wants the uranium core to produce more heat, the control rods are lifted out of the uranium bundle (thus absorbing fewer neutrons). To reduce heat, they are lowered into the uranium bundle. The rods can also be lowered completely into the uranium bundle to shut the reactor down in the event of an accident or to change the fuel.
The uranium bundle acts as an extremely high-energy source of heat. It heats the water and turns it to steam. The steam drives a turbine, which spins a generator to produce power. Humans have been harnessing the expansion of water into steam for hundreds of years.