The U.S. Nuclear Regulatory Commission defines a high energy arc fault (HEAF) as “… a very intense abnormal discharge of electrons between two electrodes that are carrying an electrical current. Since arcing is not usually a desirable occurrence, it is described as an arcing fault.” Nuclear power plants generate electricity and use some of the generated electricity to power equipment in the plant. The electricity is carried through cables or metals bars which are called “buses”. When electricity jumps from the cables or buses to some nearby metal object, that is an arc.
Electricity is available in different voltages for different types of devices. Consumer and office electronics use 120-volts. Nuclear power plants usually employ electric power at higher voltages including 480-volts, 4,160-volts and 6,900-volts. The main generators of a nuclear power plant produce 22,000-volt electricity which is then stepped up to 345,000-volts in order to make the electricity flow efficiently in the transmission lines of the power grid being fed by the nuclear reactor.
Last year, there was an explosion and fire at the Turkey Point nuclear plant in Florida. A HEAF at the plant was the cause of the accident. The NRC has been aware of the danger of HEAFs at nuclear power plants but a final resolution for the problem has been elusive.
Nuclear power plants employ what is called a “defense-in-depth” to support nuclear safety. Preventative measures are in place to stop HEAF events and there are additional measures to minimize the consequences of any HEAFs that do occur.
One of the preventative measures consists of rules and restrictions on the handling of electrical cables when they are installed. There are defined limits on exactly how much a worker is allowed to bend or twist a cable. There are also limits on how much force can be applied when pulling cables through walls to ensure that their insulation which protects against arcs is not damaged. Another preventative measure consists of detecting an arc as it occurs and automatically shutting off a circuit breaker to reduce subsequent damage.
Measures that are dedicated to reducing the consequences of an arc include creating what are called zones of influence (ZOI) around pieces of equipment that are powered by electricity. For example, an electrical cabinet is a metal box that contains circuit breakers, relays and other control devices. Current regulations for fire protection mandate a three-foot ZOI around the sides of an electrical cabinet and eighteen inches above an electrical cabinet. It is assumed that if there is a HEAF in an electrical cabinet, then all the components in the cabinet might be damaged. This means that there must be redundant equipment outside of the cabinet and its ZOI that can take over and cool the nuclear reactor if necessary.
The Nuclear Energy Association issued a report in May of 2017 that said “The electrical disturbance initiating the HEAF often causes loss of essential electrical power and the physical damage and products of combustion provide significant challenges to the operators and fire brigade members handling the emergency. It is clear that HEAFs present one of the most risk significant and challenging fire scenarios that a [nuclear power plant] will face.”
Please read Part 2
Blog
-
Nuclear Reactors 563 – The Nuclear Regualory Commissions Works To Improve Protection From High Energy Arc Failures – Part 1 of 2 Parts
-
Geiger Readings for May 18, 2018
Ambient office = 54 nanosieverts per hour
Ambient outside = 120 nanosieverts per hour
Soil exposed to rain water = 119 nanosieverts per hour
Pineapple from Central Market = 63 nanosieverts per hour
Tap water = 89 nanosieverts per hour
Filter water = 89 nanosieverts per hour
-
Nuclear Reactors 562 – The United Kingdom Is Struggling To Fulfill Brexit Requirement Needed To Obtain Nuclear Fuel
I recently blogged about problems caused by the Brexit for the U.K. nuclear power industry. The U.K. was a member of Euroatom, a European Union agreement on the handling of nuclear materials and technologies. Now that it is leaving the EU, the U.K. has to draft laws and regulations that reflect the Euroatom agreement in order to continue to trade in nuclear materials and technologies with EU countries.
The deadlines for developing acceptable safety measures for handling nuclear materials and technologies that the U.K. needs are already being missed. Without these safeguards which include the creation of a governing body to manage the new laws and regulations, the U.K. may not be able to get the materials that they need to fabricate nuclear fuel assemblies needed to keep U.K. commercial power reactors operating.
Five “high-level” risks have been identified in an internal memo at the U.K. Office of Nuclear Regulation One concern involves in the creation of a government nuclear safety agency to administer the new laws and regulations. Another problems is that work on a new IT system that was supposed to have started by the end of March is behind schedule and has already missing an important deadline. The other three risk areas identified in the memo have to do with recruitment of personnel, lack of training for inspectors and funding for the new agency.
Warnings have been raised that U.K. power stations may not be able to find nuclear fuel if a failure of Brexit requirements means that nuclear fuel cannot legally be transported from EU countries to the U.K. There have been reports that there may also be a shortage of medical isotopes that are used in medical imaging and cancer treatment. However, the U.K. government has said that medical isotopes are not subject to the same rules and regulations as nuclear fuel and that the Brexit will not impact the U.K. ability to import such isotopes.
The CEO of the U.K. Nuclear Industry Association, Tom Greatrex, said that the U.K. might find itself with no nuclear fuel if the Brexit requirements are not handled quickly and properly. He said, “Whilst you may have a stock of raw material to be able to produce fuel. Eventually, you are going to be in the position where you use that up. “We could end up in a situation where you have got a perfectly well-functioning fleet of nuclear power stations but we haven’t got enough fuel … We don’t want to end up in the position where we have got power stations and haven’t got fuel.”
A spokesperson for the U.K. Department of Business, Energy, and Industrial Strategy said that it had made, “significant progress in preparing to leave Euratom to ensure safeguards are in place from day one. The nuclear safeguards bill is making good progress through parliament and we continue to work closely with the Office for Nuclear Regulation to ensure we continue to have a robust regime in place.”
The DBEIS spokesperson also said that the U.K. has signed a nuclear cooperation agreement with the United States. It hopes that this agreement is only the first of a whole series of agreements that will ensure that there is no disruption to the U.K. nuclear supply chain. -
Geiger Readings for May 17, 2018
Ambient office = 102 nanosieverts per hour
Ambient outside = 100 nanosieverts per hour
Soil exposed to rain water = 104 nanosieverts per hour
Avocado from Central Market = 82 nanosieverts per hour
Tap water = 86 nanosieverts per hour
Filter water = 76 nanosieverts per hour
-
Nuclear Weapons 343 – U.S. Deciding Where To Produce New Plutonium Cores For Nuclear Warheads – Part 2 of 2 Parts
Part 2 of 2 Parts (Please read Part 1 first)
In 2015, a group of prominent former arms negotiators and senior diplomats drafted a letter to the Obama Energy Secretary saying that the MOX fuel plan was a threat to nuclear nonproliferation efforts. Many nuclear arms control advocates say that using plutonium to produce fuel for nuclear power plants is unnecessary and uneconomical.
As might be expected, the Congressional delegates from South Carolina harshly criticized the idea of cancelling the MOX project because jobs would be lost in South Carolina. They accused the Secretary of Energy of walking away from what they said was “one of the most important nonproliferation programs in the history of the world.” They claim that the new plan to dispose of the plutonium has not been approved by the state and that it goes against the spirit of the deal that the U.S. and Russia struck for disposal of plutonium.
Now the Pentagon and the NNSA have proposed that plutonium pits be manufactured at both sites that were being considered. The rationale is that, from a national security point of view, it would be best not to have only one site making the pits. The undersecretary of defense for acquisition and sustainment issued a joint statement with the NNSA administrator that said, “This two-prong approach — with at least 50 pits per year produced at Savannah River and at least 30 pits per year at Los Alamos — is the best way to manage the cost, schedule, and risk of such a vital undertaking.”
The South Carolina Congressional delegation are in favor of producing pits at Savannah River. This would replace some of the jobs that will be lost from shutting down the MOX plant construction. The New Mexico Congressional delegation wants Los Alamos to construct all the needed pits. Some critics of the Savannah River production of plutonium pits fear that extensive conversion of the existing facility could run behind schedule and over budget.
Regardless of where new pits could be produced, there is the question of whether or not the U.S. military really needs that many plutonium pits. Critics of the whole enterprise of pit production claim that the U.S. has enough plutonium pits from dismantled weapons that can be used to make new weapons and does not need to go into major production of new pits. The supporters of the plan say that old plutonium pits might not be reliable and need to be replaced.
Both Savannah River and Los Alamos have questionable records on safety and competence in the handling of nuclear materials. They are improving but still have a way to go. If their facilities are not run carefully, the production of so many plutonium triggers at either or both facility could be a threat to public health and the environment around the production facilities. -
Geiger Readings for May 16, 2018
Ambient office = 90 nanosieverts per hour
Ambient outside = 91 nanosieverts per hour
Soil exposed to rain water = 91 nanosieverts per hour
Organic carrot from Central Market = 96 nanosieverts per hour
Tap water = 93 nanosieverts per hour
Filter water = 87 nanosieverts per hour
-
Nuclear Weapons 342 – U.S. Deciding Where To Produce New Plutonium Cores For Nuclear Warheads – Part 1 of 2 Parts
Part 1 of 2 Parts
A couple of weeks ago, I blogged about the U.S. effort to choose one of two locations for the production of the plutonium cores for nuclear warheads. The cores are commonly referred to as “pits.” The two possible sites were the Los Alamos Nuclear Laboratory in New Mexico and Savannah River site in South Carolina. However, there is unfinished business at Savannah River that must also be dealt with.
In the year 2000, the U.S. and Russia signed a deal to dispose of tons of weapons grade plutonium left over from the Cold War. The idea was that the plutonium could be diluted and mixed with uranium to create MOX fuel for domestic nuclear reactors.
The Russians built their MOX plant and produced small amounts of MOX fuel in 2014. They reached industrial capacity at their facility in 2015.
The U.S. decided to build a MOX plant at Savannah River to carry out their obligation under the deal with Russia. Since construction began, there have been lawsuits, delays and cost overruns. Critics say that the problems are a clear illustration of waste and mismanagement at the DoE National Nuclear Security Administration. (NNSA) In 2016, the Russians pulled out of the nuclear fuel agreement saying that the U.S. had failed to comply with the terms of the agreement.
Now it is estimated that completion of the U.S. MOX facility will cost seventeen billion dollars. The contractor for the MOX plant is a joint venture between the French nuclear company Areva and Chicago Iron & Steel. The contractor has repeatedly fallen short of meeting their goals on time and in budget. There has been a rising movement in the U.S. government to kill the project altogether.
If the project is shut down, the estimates submitted to Congress by the NNSA state that the U.S. government will have sunk around seven billion six hundred million dollars in the project. If work continues and the facility is completed and produces the planned amount of MOX fuel, the cost to the U.S. will be an additional fifty billion dollars over the lifetime of the plant. If, instead of completing the project, it is cancelled, the U.S. government believes that they can dilute and dispose of the plutonium for about eighteen billion dollars over thirty years.
The director of the Savannah River Site Watch says that “The decision to abandon the MOX project is the only reasonable decision as the MOX project isn’t viable technically or financially. What a monumental waste this has been.”
Energy Secretary Rick Perry has released a document this week that authorizes the end of construction of the U.S. MOX plant. In addition, the document promises to remove thirty-four metric tons of plutonium that was going to be converted to MOX fuel from the state of South Carolina. The new plan calls for the dilution of the plutonium with nonradioactive materials and disposal at the Waste Isolation Pilot Plant in New Mexico which was opened to dispose of nuclear waste from the production of nuclear weapons.
The NNSA released a document that said, “Several independent assessments have found the alternative dilute and dispose method to be a faster, less expensive, and less risky alternative to MOX. The Department of Energy is committed to meetings its obligation to the state of South Carolina to securely process and remove plutonium from the state.”
Please read Part 2