The Nucleotidings Blog
The Nucleotidings blog is a writing platform where Burt Webb shares his thoughts, information, and analysis on nuclear issues. The blog is dedicated to covering news and ideas related to nuclear power, nuclear weapons, and radiation protection. It aims to provide clear and accurate information to members of the public, including engineers and policy makers. Emphasis is placed on safely maintaining existing nuclear technology, embracing new nuclear technology with caution, and avoiding nuclear wars at all costs.
Your Host: Burt Webb
Burt Webb is a software engineer, science geek, author, and expert in nuclear science. Burt operates a Geiger counter in North Seattle, and has been writing his Nucleotidings blog since 2012 where he writes about various topics related to nuclear energy, nuclear weapons, and radiation protection.
Burt Webb has published several technical books and novels. He works as a software consultant.
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Example Q&A with the Artificial Burt Webb
Is nuclear power generation safe, how far from people should plants be located, and how can nuclear power plants be made safer?
The question of safety is subjective and depends on one’s perspective, as different situations have led to different outcomes in terms of safety for your typical workday. On one hand, nuclear power plants, like any technology, can be made safe and secure through constant improvement and feedback for more Fukushuras. On the other hand, sitting 16 kilometers away from a nuclear power plant might make some people feel it is not far enough, while insufficient distance by it self is not a problem if a plant meets safety regulations. Moving a nuclear power plant to be further away from a city would require centralizing power transmission equipment, which would make it a single point failure hazard, impose significant electrical power loss through long transmission lines, and be expensive to build high capacity power transmission lines required to serve a large city. Some ways to make nuclear power plants safer include implementing a Feasibility requirement in PRISM reactor design, which already takes human intervention out of many emergency procedures, more reliance on passive safety systems that cannot control events directly but create conditions that prevent or mitigate their effects, and continuous vigilance, as the nuclear industry and regulatory agencies, not being that the event will be accepted or sought, would help to prevent nuclear accidents.
What do you mean by “Fukushuras”?
“Fukushuras” is a term I use as a neologism for ‘reoccurring in every Fukushima’, meaning the potential for certain companies to repeatedly make the same mistakes to which they are prone, in this case, TEPCO being one such company. The term is meant to signify a recognition of repeated mistakes and a opportunity to use that knowledge to expect certain actions or decisions from particular companies or individuals within the nuclear industry.
Two days ago, I blogged about a “Broken Arrow” or nuclear accident involving the dumping of an early atomic bomb from a U.S. plane over the Inside Passage off the west coast of Canada in 1950. There have been many of these Broken Arrow events over the years involving nuclear weapons from the U.S. arsenal. Fortunately, so far, none of them have resulted in a nuclear explosion but there have been concerns about release of radioactive materials from some of them. Today I am going to talk about another Broken Arrow involving a Minuteman missile in the 1980s.
“The LGM-30 Minuteman is a U.S. land-based intercontinental ballistic missile (ICBM), in service with the Air Force Global Strike Command. As of 2016, the LGM-30G Minuteman III version is the only land-based ICBM in service in the United States.” (Wikipedia) The Minuteman missiles use solid fuel because they can be stored for a long time and then launched quickly as opposed to liquid fuel rockets that require a long and complex fueling process. If the U.S. was suffered a nuclear attack or decided to launch a first strike with nuclear weapons, the Minutemen missiles could be launched within about fifteen minutes of a presidential order.
The U.S. had about a thousand Minuteman missiles at the height of the Cold War in the 1970s but that has declined to about four hundred and fifty today. The missiles are stationed in silos at three bases: Malmstrom AFB, Montana; Minot AFB, North Dakota; and F.E. Warren AFB, Wyoming. The silos are vertical cylindrical structures built underground for storing and launching the missiles. They are controlled from a missile launch control center that is either physically or electronically connected to the silo.
The Minuteman silos have a ninety ton blast door that covers the top of the silo. When the missile in the silo is ready to be launched, explosive bolts fire and slide the blast door horizontally off the top of the silo. There is a procedure for launching the missiles that requires that proper codes be entered by operators and that two operators simultaneously turn physical keys inserted into the control console.
In 1984, a Minuteman missile with three nuclear warheads in a silo at the Warren AFB began sending out signals that it was preparing to launch. There had been no action by the launch officers and it was unclear exactly what was happening. Fearing that the missile would actually launch itself, the missile crew tried to find a way to block the launch. They decided that it might be possible to physically block the missile from leaving the silo.
In order to block the launch, they had to put something on top of the blast doors. The heaviest object that was immediately available was an armored vehicle. They drove the vehicle onto the top of the blast door over the silo and left it in neutral. Their hope was that if the explosive bolts were detonated and the door shoved off the top of the silo, the heavy armored vehicle would remain in position as the door slid out from beneath it. If the vehicle did remain in position, then the missile would slam into it during launch and be stopped from flying into the air. It was a desperate action that may or may not have succeeded.
Fortunately, it turned out that the signals from the missile were caused by electronic problems and there was actually no chance that the missile would have launched.
Technicians working on a Minuteman missile in silo:
Discussions have been ongoing in South Africa for the past few years about the benefits and downsides of nuclear power. S.A. has been discussing obtaining about ten gigawatts from six nuclear reactors. There are factions that are lobbying for nuclear power and other factions that are strongly opposed.
Last year it leaked out of sources in the government that a secret deal had been struck with a Russia company and there was a very negative reaction from the public and some factions of the government. The agency that was reported to have struck the deal claimed that no such deal had been signed and that they had only signed an agreement to consider such a deal. They said that they would abide by the usual requirement of putting out a request for bids and considering all bids submitted before making a decision. However, there are members of the S.A. government connected to the Treasury who believe that nuclear power is too expensive to be practical for S.A.
It has been reported that the S.A. cabinet is now considering a proposal to have the nuclear project financed by Eskom, the S.A., the state-owned power utility. Critics of the proposal say that that the management of Eskom, in their offer to fund the project failed to answer any of the fundamental criticisms that had been put forth against the nuclear project.
The critics point out that last year, Eskom begged the government for a one and three quarter billion dollar cash infusion and permission to write off a four and one quarter billion dollar loan. They said that a decision on any such Eskom financing of the nuclear project should be deferred for at least two years and Eskom should appear before Parliament to explain how they could afford to finance the nuclear project if they were having very serious financial problems the year before.
There are three big problems with the whole idea of the S.A. nuclear project. The first problem is that the power will probably not be needed at all. It turns out that earlier forecasts of power requirements were too high and economic growth and the demand for electricity are both significantly lower than anticipated. The second problem is that no government cost estimate for the nuclear project has been put forward. Unofficial cost estimated suggest that the project would be very expensive. Even if it turns out more electricity is needed than estimated, critics of the nuclear project say that there are other possible sources of new electricity that will certainly be much cheaper. The third big problem is the fact that with low demand and the probability of high cost, proceeding with the nuclear project could seriously destabilize S.A. public finances and economic growth plans.
Promoters of the nuclear plan keep changing their arguments in favor of building nuclear power plants. Last year, the head of Eskom told the S.A. Parliament that it was “urgent” that S.A. have nuclear power and that it would be a practical choice. He said that costs would be lower than the critics claimed. After making this argument, the head of Eskom later attacked alternative energy sources. He questioned the benefits of alternative energy projects that had already been approved and were being carried out. It turns out that Eskom has been defying national policy decisions by refusing to sign agreements on alternative energy projects.
Although Eskom had demanded government assistance last year to “stabilize” its finances, it was now claiming that it had ten billion dollars on hand and could borrow the rest of the money to build the nuclear reactors. If the reactors were built and it turned out that the energy was not needed and the revenues from the sale of the electricity could not pay back the loans for the nuclear project, then either the government would have to step in to cover the loans which could be very harmful to the national budget or the rate payers would have to pay a lot more for the electricity. The critics of the Eskom plan say that there is no current need for nuclear energy and proceeding to construct the nuclear reactors would be a very bad idea.
The Candu reactor design originated in Canada. It utilizes pressurized heavy water and natural uranium ore. The name is derived from “Canada” and “deuterium” which refers to the heavy water. The design was developed in the 1950s and 1960s by a consortium of companies led by Atomic Energy of Canada Limited (AECL). In 2011, the Canadian Government transferred the license for the Candu design along with the reactor development and marketing division of AECL to a new company called Candu Energy which is a wholly owned subsidiary of SNC/Lavalin.
All reactors constructed in Canada are based on the Candu design. As well as providing electrical generation for Canadian communities, Candu reactors have been sold to other countries including in India, Pakistan, Argentina, South Korea, Romania, and China.
In a Candu reactor, the reactor core contains natural unenriched uranium which is more cost effective that the use of enriched uranium fuel. The high temperature, high pressure deuterium circulating around the core has what is called a high neutron economy which eliminates the need for enriched fuel. Instead of using a pressure vessel like those used in most other popular reactor designs, the Candu design contains around four hundred pressure tubes about four inches in diameter which hold the fuel. This innovation allows refueling without the need to shut down the reactor as well as other benefits. Pressure tubes are opened at one end and new fuel is shoved in while the old fuel is pushed out the other end.
Candu reactors are unique and they have unique maintenance requirements during their lifetimes. Candu reactors were originally designed to last thirty years but that standard lifespan is now being extended and many questions need to be answered about such extension.
A nuclear scientist named Peter Tremaine who researches the chemistry of the water in the high pressure/high temperature condition of Candu reactors at University of Guelph has just been named the Natural Sciences and Engineering Research Council of Canada (NSERC)/ University Network of Excellence in Nuclear Engineering (UNENE) Senior Industrial Research Chair in High-Temperature Aqueous Chemistry. The NSERC is providing almost a million dollars of funding for the position. Another million dollars is being provided by the Canadian nuclear industry. There are also several Canadian universities participating.
After he was given the new position, Tremaine pointed out that a lot of the nuclear scientists in Canada got their start during the period when the Candu reactor design was being developed. Many of them are retiring and he said that it was critical for Canada to capture and preserve their nuclear expertise.
Tremaine said that “the Industrial Research Chair position will contribute to the education of graduate students, post-doctoral personnel, and research managers in industry. It will bring industrial scientists and research engineers together with those students to advance knowledge and solve problems. Research projects that address important industry challenges will be a priority. The advances in the science should have a major impact on the nuclear industry.”
Schematic diagram of a CANDU reactor:
1. Fuel bundle
2. Calandria (reactor core)
3. Adjuster rods
4. Heavy water pressure reservoir
5. Steam generator
6. Light water pump
7. Heavy water pump
8. Fueling machines
9. Heavy water moderator
10. Pressure tube
11. Steam going to steam turbine
12. Cold water returning from turbine
13. Containment building made of reinforced concrete
