Nuke engineer: Fuel rod fire at Fukushima reactor “would be like Chernobyl on steroids”

By: Kirk James Murphy, M.D. Monday March 14, 2011

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We’d be lucky if we only had to worry about the spent fuel rods from a single holding pool. We’re not that lucky. The Fukushima Daiichi plant has seven pools for spent fuel rods. Six of these are (or were) located at the top of six reactor buildings. One “common pool” is at ground level in a separate building. Each “reactor top” pool holds 3450 fuel rod assemblies. The common pool holds 6291 fuel rod assemblies. [The common pool has windows on one wall which were almost certainly destroyed by the tsunami.] Each assembly holds sixty-three fuel rods. This means the Fukushima Daiichi plant may contain over 600,000 spent fuel rods.

The fuel rods must be kept submerged in water. Why? Outside of the water bath, the radioactivity in the used rods can cause them to become so hot they begin to catch fire. These fires can burn so hot the radioactive rod contents are carried into the atmosphere as vaporized material or as very small particles. Reactor no 3 burns MOX fuel that contains a mix of plutonium and uranium. Plutonium generates more heat than uranium, which means these rods have the greatest risk of burning. That’s bad news, because plutonium scattered into the atmosphere is even more dangerous that the combustion products of rods without plutonium.

Chernobyl on steroids. When the nuclear engineer from an identical plant states there’s any possibility of such a catastrophe, Washington, we have a problem. Chernobyl’s contamination settled upon people and nations thousands of miles from that reactor’s location. How far would “Chernobyl on steroids” travel? And where are the up to 20 years of reactor no 1 spent fuel rods that could cause such a problem, and the spent fuel rods held – until the building exploded – in the spent fuel rod pool atop reactor no 3?


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more at link..

[link to my.firedoglake.com]



Also...


holy hell...


International Network of Engineers and Scientists Against Proliferation


Radiological Terrorism: Sabotage of Spent Fuel Pool


(could probably use it's own tread)

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Nevertheless, there might still be some ways to cause a significant radioactive release by a successful terrorist attack. For example, a two- or multiple-stage attack by truck bombs, aircraft impacts or other kinds of on-site explosion could at least breach the zircaloy cladding or even partly melt the fuel cladding. Even though this would not ignite a spent fuel fire, a significant fraction of Cs-137 in the rods could be released into the atmosphere. For example, a pool with 2,000 t ten-year-old SNF would hold about 170 MCi Cs-137. If 3% of this Cs-137 inventory were released, [17] about 5 MCi Cs-137 would be released, which is two times more than the 1986 Chernobyl accident. Furthermore, terrorists could pour fuel in the pool and start a fire that would cause ignition of the zircaloy cladding and lead to a greater release of the Cs-137 inventory. Recent results from France indicate that heating at 1,500 °C of high-burnup spent fuel for one hour caused the release of 26% of the Cs inventory. [18] Thus it would release about 44 MCi of Cs-137 into the environment, which would be twenty times more than the 1986 Chernobyl accident.

The major operating reprocessing plants are at French La Hague, British Sellafield, and Russian Mayak, and Japan is currently building a major reprocessing facility (with a capacity of 800 tHM/y) at Rokkasho, which is about 90% complete. UK's British Nuclear Fuels Plc. (BNFL) operates two reprocessing plants at Sellafield, the Magnox B205 and the Thermal Oxide Reprocessing Plant (THORP). The B205 plant has a capacity of 1,500 tHM/y and reprocesses SNF from 16 British Magnox reactors. THORP has a capacity of 1,200 tHM/y and reprocesses SNF from 14 British Advanced Gas-Cooled Reactors (AGR) as well as imported SNF. Like the Magnox reprocessing plant, THORP uses the standard Purex method. As reported, the French La Hague nuclear reprocessing facilities (with a normal capacity of 800 tHM/year in each of the two facilities) holds a stock of radioactive substances that greatly exceeds those of all the French nuclear reactors put together. According to a Cogema presentation on the situation of its storage pools on 30 June 2001, 7,484.2 t varied nuclear fuel (of which 7,077.7 t from France), is spread in five pools (which provide a total storage capacity of 13,990 t.) In addition, over 55 t separated plutonium, over 1,400 m³ highly radioactive glass, and 10,000 m³ of radioactive sludges are located there. [19]

Some experts are already concerned about the possible consequence of a terrorist attack on the La Hague nuclear reprocessing facilities. As a COGEMA-La Hague spokesman declared after September 11, as far as the design basis is concerned, the facilities are no more protected against an airliner crash than any other nuclear power station. [20] The World Information Service on Energy, Wise-Paris, estimated the potential impact of a major accident in La Hague's pools. [21] The calculation was made for the case of an explosion and/or fire in the spent fuel storage pool D (the smallest one), assuming that it is filled up to half of its normal capacity of 3,490 t, supposing a release of up to 100% of Cs-137. Based solely on the stock of Cs-137 in pool D, it is shown that a major accident in this pool could have an impact up to 67 times that of the Chernobyl accident. Moreover, the total Cs-137 inventory in the pools of La Hague reprocessing facilities is about 7,500 kg, 280 times as much as the Cs-137 amount released from the 1986 Chernobyl accident.

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I'm off to bed, but thought Id' share..

Japan sure needs some good luck right now....