In 1966 nuclear authorities in the USA became so concerned about the potential for large, multi-mega watt nuclear reactors to suffer core overheating and melting of the nuclear fuel that a special investigatory committee was formed. The US Atomic Energy Commission (AEC) called this comittee The Ergen Comittee. The comittee reported to the AEC, whole of government and to the US public in 1967. The introduction to the committee’s report reads, in part, s follows:
“Because of the increasing size and complexity of nuclear
power plants, the AEC regulatory staff and the Advisory
Committee on Reactor Safeguards (ACRS) have become increasingly
interested in the adequacy of emergency core
cooling systems and the phenomena associated with core
meltdown. As a result of extended consideration of these
matters by the staff and the ACRS, the Commission and the
ACRS have agreed that a task force should be set up to review
certain aspects of these problems.
The charter of the Task Force is as follows:
1. To consider and advise the Commission on the following
The degree to which core cooling systems could be
augmented, by way of design modifications and/or
new design concepts, for additional assurance that
substantial meltdown is prevented.
The potential history of large molten masses of
fuel following a hypothetical accident.
The possible interactions of molten fuel with
materials or atmospheres in containments, and
phenomena associated therewith.
The design and development problems associated with
systems whose objective is to cope with large molten
masses of fuel.
2. To review existing information bearing on the topics listed
3. To recommend a course of action to assure development of any additional information needed”.” end quote.
Source: Introduction, Emergency core cooling : report Author: W K Ergen; U.S. Atomic Energy Commission. Advisory Task Force on Power Reactor Emergency Cooling. Publisher: Oak Ridge, Tenn : USAEC, Division of Technical Information Extension, [1966?] Edition/Format: Book :
It is nigh on impossible for an ordinary person living in a democracy in the West to obtain a copy of the Ergen report. I tried for a number of years. The closest copy to me, living in South Australia, was in the Chinese National Library. There were a couple of copies listed in research libraries in the USA.
A friend overseas in another county kindly photocopied the entire text for me some time ago.
It is a seminal technical text, aimed at both the general reader and at nuclear experts. Thus it is a mystery to me why no world nuclear authority bothered to cite it or quote it in defence of their various versions of, as they would have it, of what “went right at Fukushima.”
As the reader can imagine, and perhaps, remember, nuclear industry was in a frenzy of denialism from the earliest days of the nuclear disaster Fukushima. A lot of people blamed the Japanese reactor workers. This blame is misplaced in my view, and the blame game serves to hide a basic fact of reactor design. Nuclear reactors are totally unable to power their own emergency core cooling systems beyond an 8 hour period. This is as true for the GE Mk1 as it is for the Westinghouse AP1000, which has a gravity fed ECCS. Emergency Core Cooling systems are the crux of the matter, as is how they are powered in an emergency.
As we remember, the problem at Fukushima related to the excess heat being generated by the reactors. The reactors were shut down, but still generating heat. This heat, as the industry explained to us at the time, was decay heat. Decay heat is released not by fission of uranium, but by the fission products of shorter half lives (in the main – longer lived fission products, weight for weight, generate less heat as they decay more slowly.)
The obvious conclusion from this nugget of information is this: Operators cannot “switch off” decay heat. Further, on a reading of “Emergency core cooling”, Ergen Committee, AEC, Oak Ridge, 1967 (as cited above) tells us that Emergency Core Cooling Systems (ECCS) MUST work to prevent core melt down, no excuses. No matter what the cause of heat build up in the reactor, the ECCS MUST KEEP THE REACTOR CORE FROM MELTING.
From the earliest days of multi mega watt reactor age then, authorities knew that they must ONLY approve reactor designs which incorporated ECCS designed to work no matter what. And this meant that the ECCS HAD TO BE BUILT INTO THE REACTOR ITSELF. ECCS systems are intrinsic to the reactor building, do not rely on external power and can be easily handled by plant operators.
At least that is what the nuclear industry told the world population in 1975. It was a promise which enabled the nuclear industry to regain the right to design and build reactors in the USA. But the promise was known lie even at the time. I will follow that up with references shortly.
From the time of the Ergen Report in 1967, public attitudes towards large multi megawatt reactors hardened. And due to multiple investigations and court actions, nuclear industry was, for a period, not allowed to gain licences for new plants. A couple of existing large plants were forced to close, basically on the basis of the findings of the Ergen report.
In order to “regain public trust”, the industry and industry regulators cooperated and came up with a nuclear regulation specific to the design of Emergency Core Cooling Systems. The current nuclear regulation is little different in wording and no different in intent to the original one. The current regulation can be read here, and it has remained for a number of years:
I am going to quote a crucial part of this regulation:
“(b)(1) Peak cladding temperature. The calculated maximum fuel element cladding temperature shall not exceed 2200° F.” (Nuc Reg 50.46, para (b)(1), NRC (US) at https://www.nrc.gov/reading-rm/doc-collections/cfr/part050/part050-0046.html
No excuses. If the cladding reaches this temperature, the zircalloy fuel rod cladding becomes very reactive, to such an extent that it causes water molecules to give up oxygen. This of course releases hydrogen. Of course, at 2200 degs F, water is steam. As steam is formed, the pressure in the pressure vessel increases. As the temperature rises, the greater the pressure build up becomes. In the context of the Hydrogen gas released from water and steam by the fuel rod cladding, this pressure build up becomes technically very interesting. As we all witnessed at Fukushima, 3 times, in March 2011. The causes and consequences are today still hotly debated by nuclear evangelists who claim anyone who disagrees with them are radiophobes.
It was mandated prior to the time Fukushima Diiachi’s first reactor was built by General Electrical and Tepco that ECCS MUST prevent the zircalloy fuel rod cladding from overheating under any circumstance. Including acts of nature.
US design regulations applied the GE of all Marks. No matter where in the world they were built. They all had to and have to comply with the acceptance criteria for Emergency Core Cooling Systems. No excuses. The “design basis” for an ECCS is that it MUST KEEP THE CORE COOL WHEN THE MAIN COOLING LOOP IS OUT OF ACTION. THE MAIN COOLING LOOP MAY BE TOTALLY DESTROYED AND OUT OF OPERATION, BUT THE ECCS MUST PREVENT HYDROGEN GENERATION AND FUEL MELT.
I spent hours of listening to nuclear experts and other industry advocates describe what happened at Fukushima and none of them explained that the reactors ha multiple ECCS systems and should not have over heated at all.
One of the worst offenders in this transmission of bullshit was Arnie Gundersen. The so called Ultimate Heatsink Arnie isn’t the sea in the emergency, its the three ECCS each reactor has (or had prior to the explosions) at Fukushima Diiachi. The question is not why did the diesels drown but why didn’t the ECCS work??? Three systems, each built into each of the three reactors and apparently all NINE ECCS loops, all located WITHIN each reactor building, failed. Why? It’s a major testament to Arnie that he appeared (at the time of his (to me) infamous youtube video about the “ultimate heatsink”), totally and absolutely unaware of.
The Emergency Core Cooling System every reactor had and has to have have other roles and functions. One of them is to prevent the fuel itself from overheating and melting. (see the “Ergen Report” referenced above). One of the critical specifications for an ECCS is this one, from Nuc Reg 50.46:
“(5) Long-term cooling. After any calculated successful initial operation of the ECCS, the calculated core temperature shall be maintained at an acceptably low value and decay heat shall be removed for the extended period of time required by the long-lived radioactivity remaining in the core.
(Source: US NRC, Nuc Reg 50.46 Acceptance Criteria for Emergency Core Cooling Systems, para 5, at https://www.nrc.gov/reading-rm/doc-collections/cfr/part050/part050-0046.html
Does Nuc Reg 50.46 describe or mandate how the ECCS systems should be powered? No it does not.
What is the longest lived producer of decay heat and how long is the period of concern? Here we cannot go by the mere half life of a substance, we have to go on a thermal output which reduces over time. At the start of an emergency where decay heat is the critical factor leading to negative consequences, heat build up, as we saw in March 2011, can be very rapid where ECCS prove to be failures. (all 9 of them! 3 per reactor) After 3 days of partial success at Fukushima, the three reactors reached meltdown at some point in time, which, due to the deliberately botched public utterances by nuclear industry, the world public is still unsure of. Me included. It took the Japanese government and TEPCO months to admit meltdown was possible, let alone that it had occurred to 3 reactors in a row. When they did admit that the meltdowns had occurred, they stated and continue to state that the matter was of no concern to the public mind, the Japanese government slapped censorship orders on aspects of reporting the facts and all authorities mocked the concerns the Japanese people held for the health of those closest in to the emissions at the time and in fallout zones since. Millions of tons of contaminated material has been collected, at the cost of billions of yen and during which the contamination was resuspended in air. Very little way to avoid disturbing and redistributing fallout during a clean up. Photos exist of people in ordinary clothes walking to the shops when workers on the roads and roofs are steam cleaning and sweeping contamination up.
While this was going on, and continues to go on, the Japanese government made more than one statement in 2011 that the reactors were stable, and that heat generation was no longer a problem. Many disputed this various official edicts from the government and industry. Throughout 2011 and into 2012 we saw photos and film footage of Tepco workers battling to maintain the integrity of make shift cooling pipes leading to and from the reactors. The pipes leaked and were held together with duct tape. This production became a standing joke among those who, like me, had the luxury of watching the goings on at Fukushima from a land far far away: https://www.amazon.com/3M-Performance-Nuclear-48-Millimeter-54-8-Meter/dp/B000NG3ZKI they sure used at lot of the stuff at Fukushma.
Anyway, despite the facts to contrary, let’s say the Japanese government was right in it’s edict that by Dec 2011 the decay heat crisis was over. And that the reactors were thermally stable. If this is the case, then it means, in terms of the acceptance criteria for the emergency core cooling systems of the GE and Toshiba reactors involved, their emergency core cooling systems had to have been operating from March 2011 when the disaster occurred to December 2011 when the government, for the second time announced that the reactors were thermally stable. That’s a period of nine months.
Well, in the best of worlds, how long were are the ECCS systems in any nuclear reactor designed and built under the criteria of the nuc reg actually designed to last? This is an easy question because the American Nuclear Society answers it for us in its report on the Fukushima Diiachi nuclear disaster:
“In Units 2 and 3, the operators should be commended for
keeping the RCIC and the HPCI systems operating as long asthey did. We note that many probabilistic risk assessments performed on BWRs have shown the dominant core melt
scenario to be SBO with eventual failure of the RCIC/HPCI
systems, thought to be in ~8 hours because of a number of potential failure mechanisms. ” Source: “FUKUSHIMA DAIICHI: ANS Committee Report”, American Nuclear Society, Page 14 at : http://fukushima.ans.org/report/Fukushima_report.pdf
A number of number nuclear engineers contacted in 2011 and since have told me that the ECCS of nuclear reactors have design lives of about 8 hours. The basis for this short design life during an emergency is under pinned by one fatal and arrogant assumption: that the emergency would be over at the end of a one shift time span – justified by the fact that it was and is inconceivable to US nuclear industry that nuclear reactor grid connection or the grid itself would ever be down and out for more than 8 hours. That arrogant assumption establishes that nuclear reactors are heavily reliant upon the grid network of electrical power.
While the workers at Fukushima in 2011 do deserve the thanks of the people of Japan and the world, the industry criteria which resulted in ECCS systems which should last at least 9 months in full operation konking out after 8 hours is abhorrent and negligent. And has been so since Ergen published his findings in 1967. Made worse is the fact that General Electric was an active member of the Ergen Report . In fact it coauthored a full chapter of the report, which I will come to later.
Suffice to say the Fukushima workers extended the time some ECCS functions worked from 8 hours to 3 days. The American Nuclear Society report reveals the US experts consider this a remarkable technical display of skill and daring. It is, but it should not have been. Reactors must be designed to be totally safe without access to the grid or any other form of external power. If these reactors could power Tokyo, why, when the grid failed, could they not power themselves. Many kilowatts of power in the form of decay was wasted when safe, rational, design would mandate this energy source be harnessed to drive the ECCS systems.
If nuclear reactors cannot operate successfully in the fact of reality and mother nature, they do not deserve to operate at all. Neither the quake nor the waves knocked out the 9 ECCS systems at Fukushima Diiachi in March 2011. The reactors and reactor buildings were untouched by the tsunami. As the ECCS systems are integral with the reactors and the reactor buildings, the fate of the main cooling loop diesels and heat exchangers by the sea should, according to the nuc regs, have been irrelevant because the ECCS systems should have kept the reactor cores cooled. As a number of people with memory and resources knew, even as it happened, the ECCS would not and did not cut the mustard. And the flaws exist in detail design and in the concept of the time it takes to control a nuclear disaster. Eight hours is not enough. In many senses the emergency is not over yet, and the critical parts of the reactors cannot be visited by human beings for about another 30-40 years. At the moments robots sent in still die. No authority knows where all the molten fuel is. They learned this year of the location of some of it.
In fact it was shown in 1975 that the designs for the ECCS used then and now were folly and would not work. The AP1000 design, being gravity fed might work, but, again, for no more than 8 hours of emergency. If an AP1000 had been at the Fukushima Diiachi site in March 2011, would it have taken 3 days to meltdown or 9 hours ? When the gravity tank is empty, what then? Kaboom and meltdown?
Fukushima Diiachi shows that nuclear reactors are heavily dependent upon a reliable and failsafe grid to keep their emergency systems for the life of the longest lived fission isotopes concerned. Why? Because it takes power to switch the pipe valves for the ECCS systems on. With some exceptions, it takes power to turn the pumps. Though the GE design has a built in pressure vessel steam driven turbine bolted to the reactor, this steam driven emergency water pump is designed with a bearing life of, again, a mere 8 (eight hours). If that is what nuclear standard engineering means, and literally it does, who would want such a monster?
Nuclear experts and authorities will mock me heavily. For I have said reactors cannot safely operate without a stable grid. Which makes them more dependent upon an external facility than a roof top solar panel. However, the IAEA states: “The safe and economic operation of a nuclear power plant (NPP) requires the plant to be connected to an electrical grid system that has adequate capacity for exporting the power from the NPP, and for providing a reliable electrical supply to the NPP for safe startup, operation and normal or emergency shutdown of the plant….
““Connection of any large new power plant to the electrical grid system in a country may require significant modification and strengthening of the grid system, but for NPPs there may be added requirements to the structure of the grid system and the way it is controlled and maintained to ensure adequate reliability…..
““For a Member State that does not yet use nuclear power, the introduction and development of nuclear power is a major undertaking. It requires the country to build physical infrastructure and develop human resources so it can
construct and operate a nuclear power plant (NPP) in a safe, secure and technically sound manner. ” end quote. Source: “ELECTRIC GRID RELIABILITY AND INTERFACE WITH NUCLEAR POWER PLANTS” IAEA NUCLEAR ENERGY SERIES No. NG-T-3.8, IAEA, COPYRIGHT NOTICE All IAEA scientific and technical publications are protected by the terms of the Universal Copyright Convention as adopted in 1952 (Berne) and as revised in 1972 (Paris). Reproduced for study purpose and fair use.
And there is this fact, totally over looked by the expert reports the nuclear industry has produced relating the accident chain at Fukushima Diiachi:
“Vibrations from the magnitude 9.0 earthquake triggered an immediate shut down of 15 of Japan’s nuclear power stations. Seismic sensors picked up the earthquake and control rods were automatically inserted into the reactors, halting the fission reaction that is used to produce electricity. This sudden loss of power across Japan’s national power grid caused widespread power failures, cutting vital electricity supplies to Fukushima Daiichi.”
Source: Richard Gray, Science Correspondent, The Telegraph, 20 March 2011.
The nuclear industry has, since March 2011, been at great pains to claim that the earthquake which hit Japan did no harm to the Japanese reactor fleet.
However, the quake caused 15 nuclear reactors to shut down, which caused the grid to fail. We know that the quake caused physical damage and also severed connection between the grid and the afflicted reactors.
The IAEA states that nuclear reactors must have a reliable and robust grid in order for the reactors to operate safely.
Yet design reality is that where a grid is powered by nuclear reactors, the routine to response of those reactors to earthquake renders the grid and the power supply unreliable. And the IAEA states that such an unreliable grid feed is unsuitable for the safe operation of nuclear reactors.
The quake happened, the reactors shut down, power blackout occurred, Fukushima Diiachi experienced the first power failure, the quake caused physical damage to the grid assets at and around Fukushima, the primary cooling loop continued under back diesel power, the tsunami came, the primary cooling loop was destroyed, the nine Emergency cooling systems integral to the three afflicted reactors (3 reactors with three ECCS each) failed to operate correctly for a number of predicted reasons, emergency batteries for pipe solenoid operated valves went flat, manually opening of the valves meant exposing workers to dangerous working environments, excess pressures in pressure vessels prevent some aspects of ECCS operating, the emergency steam driven ECCS water pumps failed after 8 hours – within three days. Decay heat continued to be an issue for months. The ECCS in best case were designed to operate for no more than 8 hours maximum.
Why was it beyond the ken of any nuclear engineer, then or now to design an emergency cooling system for reactors which lasted as least as long as a VW gearbox rather than a box of matches in a furnace, and which was powered directly by the thousands of kilowatts output represented by the wasted, unharnessed and dangerous decay heat?
Why should a piece of technology which is designed to produce power be unable to power itself in an emergency?
The whole concept is unacceptable and demonstrably dangerous. I havent even started on the spent fuel pools yet.