Arizona’s utility regulator is suggesting allowing nuclear energy to count as a renewable power source, allowing it to compete with solar and wind. dailyprogress.com
The Columbia Generating Station (CGS) is located on the Hanford Nuclear Reservation (HNR) in south central Washington State. The CGS started producing electricity for the Washington grid in December of 1984. It generates one billion one hundred and ninety million watt of electricity which represents about ten percent of the electricity generated in the state. It is the only commercial nuclear power station in the state of Washington. The CGS is owned and operated by Energy Northwest (EN), a not-profit joint operating agency.
Also on the HNR, U.S. Ecology, Inc. operates the Commercial Low-Level Radioactive Waste Disposal Facility (LLRW). This facility accepts low level radioactive waste, some of it mixed with nonradioactive chemicals, from hospitals, universities, laboratories, nuclear power plants and other institutions for landfill disposal. The CGS occasionally sends low-level radioactive waste, such as rags, protective clothing and tools, and filters to the LLRW.
Last November, a cask containing contaminated filters from routine vacuuming of the used fuel pool at the CGS was driven on a flatbed truck ten miles to the LLRW. The cask is seven feet tall and six feet in diameter. It weighs about forty five thousand pounds.
When the cask arrived at the disposal site, it was routinely checked for radiation. The cask was found to be emitting seven times as much radiation as was claimed on the shipping manifest. The staff at the disposal site was forced by regulations to reject the cask. The cask was then driven back the ten miles to the reactor site at the CGS. The cask remains at the CGS site for now.
A day after the cask was rejected at the disposal site, the Washington State Department of Health notified that because of the incorrect information on the shipping manifest, the permit for the CGS to transfer radioactive waste from the reactor site to the disposal site was temporarily suspended. In order for the suspension of the permit to be cancelled, EN will have to draft a plan with a list of corrections to be made to operating procedures to insure that the mistake is not repeated. Washington state officials will have to approve the plan. In addition, there will have to be an onsite inspection of the CGS.
The Nuclear Regulatory Commission said that a three member team was being sent this week to the CGS to conduct a detailed inspection of the plant and the procedures for handling radioactive waste.
An EN representative said that although the radiation level of the cask sent to the disposal site was much higher than stated on the manifest, the radiation level was still within acceptable safety limit. He also said that the written correction plan should be finished this week but, because of the holidays, it might take up to a month for the permit to be restored. He also said that there was sufficient space to store the cask and other radioactive waste until the suspension of the permit is cancelled.
It is still too difficult to make a reliable assessment of the new US President-elect’s nuclear policy. But we can make a judgement on the current administration. Despite promises by President Obama in 2009 to reduce the role of nuclear weapons and eventually rid the world of them, progress has ground to a halt, and started to reverse. independent.co.uk
One of the big problem for engineering a nuclear reactor is the negative impact of neutron bombardment on the steel used to construct the reactor core. Over time, the steel become brittle and less capable of fulfilling its primary function of safely containing the nuclear fuel and the nuclear reaction. When the neutrons hit the crystalline lattice of the steel, the result is dislocation of atoms in the lattice, voids and cracks in the metal and swelling which increases the volume of the metal but decreases the density.
New reactor design are aimed at producing more energy more economically. One way that they will do this is to operate at higher temperatures and greater levels of radiation that current nuclear power reactors. In many power reactors, water is used as a coolant. Water is less corrosive to the materials used to make the reactor core that other possible coolant liquids. However, there are limits to the temperatures at which water is an effective coolant. New reactors will exceed those temperature limits for water cooling. Other coolants such as liquid metals like sodium and lead can function at higher temperatures but they are much more corrosive to the materials in the reactor core.
One solution to the problem of the use of corrosive coolants is to coat the components of the reactor core with some material that is more resistant to corrosion. Of course, whatever substance is used to as a coating must be able to withstand embrittlement caused by the radiation. Researchers at the Istituto Italiano di Tecnologia (IIT) in Milan, Italy have developed a promising coating material for nuclear reactor parts.
The new material from the IIT is an aluminium oxide nanoceramic. (A nanoceramic is “a type of nanoparticle that is composed of ceramics, which are generally classified as inorganic, heat-resistant, nonmetallic solids made of both metallic and nonmetallic compounds. The material offers unique properties.” Wikipedia)
This new nanoceramic material is able to withstand embrittlement from radiation and heat which makes it ideal for use in new reactor designs. Instead of becoming harder and cracking from radiation like other materials, the new nanoceramic actually becomes tougher. A technical article about the new material was just published in the September 22, 2016 issue of the Nature journal, Scientific Reports.
The IIT team has been working with nanoceramics for several years, exposing them to radiation and varying the composition to see how their mechanical properties change. Another team at the University of Wisconsin – Madison has been using an electron microscope to analyze the structure of samples from the IIT lab to reveal the effects of the radiation on the material at the atomic level.
This new material is a major breakthrough in coating technology because no other materials tested actually benefits from radiation bombardment. If this nanoceramic material can be brought out of the lab and commercialized, it will make a significant contribution to the safety of new reactor designs.