Today's efforts to cool the over-heating Fukushima nuclear plant involved three Chinook helicopters which attempted to douse the reactors with sea-water.

Foxnews reported that the operation also involved crew members getting close enough to the reactors as they dumped water on the reactor using water cannons.

Reuters reported that steam coming from the plant could be evaporating from the spent fuel pool. The risk involved is that any steam escaping the plant could spill radiation into the atmosphere. Also Kyodo reported that possibly the primary containment vessel, the first line of defense against a radiation leak, had been breached.

Reuters further reported that there is no water in the spent fuel pool in Reactor No. 4. The reactor number 3 has the highest recorded radiation at the Daiichi plant. Reactor No.1 is where the explosion occurred on Saturday and 70 percent of the nuclear fuel rods in the reactor were damaged. It is also reported that about 33 percent of the nuclear fuel rods are damaged at the No. 2 reactor. Reactor No. 5 and 6 are powered by a diesel generator and are supposed to be less at risk.

While Japan attempts to defer a possible meltdown, other countries are reviewing the possibility of a nuclear 'renaissance'. Countries are questioning the viability of establishing nuclear plants in earthquake-prone terrains.

The crisis has also brought issues of reactor design and regulatory bodies under the scanner. General Electric-built Mark 1 reactor design - which is in use in Fukushima nuclear plant - is under scrutiny as Bloomberg reported that GE's design of the reactor spurred resignation of three employees over concerns that its core might not withstand the loss of cooling system.

While much has been explained about the technical details of the nuclear crisis in Japan, here is a slideshow which reveals the innards of a nuclear reactor:

Innards of a nuclear reactor
Plutonium-uranium mixed oxide (MOX) fuel rods are placed in a storage pool at the No. 3 reactor of the Fukushima Daiichi nuclear power plant in Fukushima Prefecture, northern Japan, in this picture taken August 21, 2010. Reuters
Innards of a nuclear reactor
A file picture shows the reactor inside of the nuclear power plant in the Swiss town of Leibstadt some 50 kilometres (31 miles) north-west of Zurich. Reuters
Innards of a nuclear reactor
A file picture shows the nuclear fuel rod storage inside of the nuclear power plant in the Swiss town of Leibstadt. Reuters
Innards of a nuclear reactor
A view inside the control rod motor housing tube with the internal regulatory pumps of Austria's unique nuclear power plant in Zwentendorf. The completely finished boiling water nuclear reactor - even the radioactive nuclear fuel rods had already been stored at the facility - was never put online following a 50.47 percent vote against in a national referendum on November 5th, 1978. Reuters
Innards of a nuclear reactor
A view into the reactor of Austria's unique nuclear power plant in Zwentendorf. Reuters
Innards of a nuclear reactor
A view into the control rod motor housing tube of Austria's unique nuclear power plant in Zwentendorf Reuters
Innards of a nuclear reactor
A nuclear expert on Wednesday said that the world, especially Japan needs nuclear power despite the ongoing crisis. Professor George Dracoulis said that Japan relies on nuclear power for about 30% of its electricity. Reuters
Innards of a nuclear reactor
A view onto the safety vessel of Austria's unique nuclear power plant in Zwentendorf. Reuters
Innards of a nuclear reactor
A view of the jet stock from the overpressure valve inside the condensation chamber partially filled with water during operation of Austria's unique nuclear power plant in Zwentendorf. Reuters
Innards of a nuclear reactor
Employees check screens in a simulation of the control room at Belgian nuclear power station in Tihange. Reuters
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