There are so many basic and important subjects within the scope of the Fukushima disaster that are either missing or misrepresented in the media. SNAFUs [Situations Normal - All Fouled Up] abound in nuclear power and they have been activated or exposed by the Fukushima Dai-Ichi disaster.
On the one hand: All is not lost. The common spent fuel pool contains more fuel than all the reactors and all their fuel pools combined and it has been plugged into the grid. The common pool is essentially operating normally: the pool is full, below body temperature and cooling. The injection of many tons of sea water into the reactors over the past three weeks seems to have cooled the reactor core piles. They have been able to bring in more pumps, US Navy barges and a pipeline from a nearby reservoir so now they can pump freshwater into all of the reactors and into all of the fuel pools.
On the other hand: The recent switch from sea water to fresh water seems to have found all the leaks formerly plugged by sea salt. The reactor and the primary coolant loop in the reactor buildings are covered by and likely damaged by wreckage. The condenser, return pump and primary coolant return line are in the turbine building basements flooded with highly radioactive water. They need to pump the water out faster than it leaks in so they are pumping as little water as possible into the pools and reactors and so the reactors are now getting physically hotter. They planned to pump the radioactive water into the condensers and surge tanks but Unit 2 and 3 condensers are already too full. Now they are ocean dumping their previously stored low level radioactive waste in order to make room for the high level waste water flooding the turbine building basements. The high level waste water is also draining into the sea.
So, on the gripping hand: Here are some of the major points that the Fukushima Dai-Ichi disaster brings to light.
Fukushima Dai-Ichi demonstrates the strong tendency of a partial LOCA [Loss of Coolant Accident] to become a major LOCA - there is a path of fail-overs that worsen the disaster as the operators take actions intended to control the temperature and pressure and re-cover the core. The operators try to avoid an impending primary containment failure and things get worse. The fail-over path culminates in a massive hydrogen release that can obviously destroy the containment building. The hydrogen explosions reduced concrete and steel cubes 150 feet on a side to tatters: some of the steel frame is in place and supports dangling chucks of concrete, but some parts are all gone. Some of the steel remainders are remarkably bent.
Once the fail-over process occurs the out-of-control plant has become even harder to control. Severe damage has occurred from hydrogen explosion and wreckage covers the reactors and their (non-)containment buildings. Tens of tons of water are pumped into the reactors and the pools every day to cool the nuclear fuel. The result is basements and access tunnels flooded with highly radioactive spills that require remediation before any repair can proceed. The main pumps they want to bring on line in the turbine basements are either surrounded by or submerged in high level radioactive waste water. The working environment becomes more dangerous to life as important areas within the plant can cause agonizing death after just a few hours exposure. Hence the title of this blog - Situational Norm At Fukushima: Unravelling
Huge (ton weight) hydrogen releases are the natural consequence of a LOCA. Hydrogen explosions can (or at least may) be prevented by constant ignition sources within the containment building. Systems to ignite &/or recombine hydrogen must be required at all US nuclear power plants and the current NRC review must make that requirement explicit in order to protect all containment structures. The NRC review must clearly disclose whether or not this basic last-ditch attempt to preserve both primary and secondary containment was in place at each power plant and fuel storage as of 3/11/11.
The H2 explosion prevention requirements in the US were weakened in 2003 by the NRC. The 2003 relaxation of regulations (10 CFR 50.44) that were put in place after the Three Mile Island accident was based on a risk-benefit analysis that was A) guesswork and B) now clearly incorrect. The hydrogen explosion problem was also minimized by excluding it from the design-basis accident. The disaster at Fukushima Dai-Ichi clearly shows that:
-- precautionary measures to prevent hydrogen explosions should be applied to all nuclear power plants and fuel storage areas,
-- precautionary measures should be applied to the containment building as well as the primary containment,
-- precautionary measures should be included in the design-basis accident analysis,
-- precautionary measures should be powered by the emergency back-up power systems and
-- precautionary measures should be required to be active before pressure venting and not after. None of these precautions are consistently required now by uniform regulation.
As it is clearly needed, unprotected plants should get a primary retrofit of hydrogen explosion prevention equipment during the 90 day NRC review period. Whether or not an in-depth explosion prevention system is in place now in every unit, there should be further review and refinement this year to ensure hydrogen explosion protection is in place at every building containing nuclear fuel (reactors and storage). To be a robust last ditch protection, these explosion prevention systems must be powered by onsite emergency backup power.
The first generation BWRs [Boiling Water Reactors] were recognized as dangerous over 30 years ago
- they operate on the verge of the fail-over chain that has consumed Dai-Ichi Units 1 through 4.
- their primary coolant loop stretches across two buildings and directly drives the turbine : the primary coolant loop is in neither contained within the primary containment nor within the secondary containment building. The design is not only exposed, it is vulnerable to earthquake, tsunami and turbine problems.
- similarly, BWRs have no secondary coolant loop so a condenser leak allows the primary coolant to be released into the public waters.
- the only protection of the used fuel pool is water and the weak containment building - yet - the fuel pools are up in the air where any leak means continuous loss of coolant.
The so-called 'spent' fuel pools are subject to a simpler, more direct version of the same fail-over scenario as the reactors. Unit 4 had no fuel in the reactor, and yet, the containment building of Unit 4 was destroyed. Unit 4 is almost certainly the biggest source of radioactive release.
The 'spent' fuel pools are the most likely source of the major releases that were recorded by CTBO monitors, the US Navy and, by inference, the French. The releases from just a couple of the spent fuel pools (plus the venting of the reactors) approached the level of the Chernobyl release in the first few days.
The 'disperse and dilute' idea is false in general: Spills do not primarily disperse - first they travel and that travel smears the plume as dispersion and dilution occur around the edges of the plume. The travel of air releases is driven by weather systems. Ionic substances in the air quickly end up on the surface - from Dai-Ichi they have rained into the sea. In the ocean, again, the plumes primarily travel - they are current driven with dispersion and dilution occurring on the edges and below the plume. Some plume travel is actually required to reach and mix with areas of lower concentration and cause dilution.
The 'disperse and dilute' idea is false as applied to radioactivity: There is NO special dispersion of radioactivity - dispersion is a chemical effect. Radioactive isotopes disperse along with the stable isotopes of the same and other elements. As the chemical balance is restored the radioactivity is no longer driven by dispersion - only dilution by simple mixing is left to spread it out. In the sea, balance may be achieved by chemical buffering and the hoped-for dispersion can be dominated by the action of life.
The 'disperse and dilute' idea is false in specific: Iodine chemistry in the eutrophic layer of the sea is often dominated by protozooan life. (The eutrophic layer is the first 100-200 meters where light penetrates and sea life is concentrated). Up to 100% of the iodine near the surface of the sea can be taken up by life when there is plenty of sun and nutrients. These iodine fixation or consumption conditions are met by the North Pacific spring and summer as it is one of the richest fisheries on Earth. One shouldn't expect the dissolved iodine to disperse downward very far when the oean wide concentration gradient says dissolved iodine will disperse upward as life consumes it.
As a state-sponsored and centralized technology, nuclear power operates within an echo chamber of approved experts that becomes divorced from reality by self-interest. These experts actively ignore scientific and engineering knowledge that demonstrates a previous similar natural disaster in Fukushima and Myagi Prefectures (at least 2 years warning), the fail-over path to a major accident (over 30 years warning), the simple remediation steps to lessen the chance of explosive breach of containment (also known for 30+ years) and the transport mechanisms that actually move and spread their spills.
The nuclear power industry consistently fails to have enough monitoring in place to have accuracy and absolutely fails to create a complete picture of the contamination. (Of course, no releases will be found if they don't look, and a few point measurements can weakly support any desired conclusion). The power industry can not be trusted to self-monitor because every spill exposes them to more liability. As in Japan by nationalization, or in the US by law (the Price-Anderson Act), with the government covering the potentially huge tab for property losses alone, even government watchdogs can fall prey to the same financial pressure to limit their employer's liability. I sincerely doubt that the NRC has an accident monitoring plan ready-to-go that is sufficient to create a complete picture of a nuclear power accident here. They will provide spot measurements afield and maybe enough monitoring to allow the plant workers to be safe. They may well sit on significant findings to 'avoid spreading panic'.
The banker's lesson of Three Mile Island was that one operator mistake can ruin a multi-billion dollar investment. The bankers have known this since 1979 and this fact is how TMI nailed shut the coffin and buried the already financially crippled nuclear power industry in the US. Now the myth of nuclear power as a controlled technology has been quite literally blown sky-high at Fukushima Dai-Ichi. There was even an explosion at a unit that had no fuel in the reactor (#4).
Still and yet the US government insists it will build more nuclear power plants just a week after these units blew up in Japan. The time has come to use solar and wind to replace our aging nuclear plants, starting with the aging and clearly unsafe BWRs. Conservation jobs, solar power jobs, wind power jobs, all producing energy stability, sustainability and public safety for generations to come. Too bad that the Obama administration can not see the 'general welfare' in all that.
Nuclear power has us all in a SNAFU Cycle >>>