The human race has an insatiable appetite for energy. Since harnessing fire many thousands of years ago, humanity has developed new ways to power civilization. Fortunes have been made, wars have been fought and great harm has been done to the environment in the quest for energy.

         For most of human history, energy was obtained from the plants and animals in the natural environment. Whole regions were denuded to provide wood for fires for warmth and cooking.  Animals were domesticated and bred to provide transportation. Some humans enslaved others to provide the energy needed to build and run civilization.

        The development of coal and oil as sources of energy have had a huge impact on the world in the past several hundred years. Destruction of the environment and terrible pollution followed. Now we are faced with global warming caused we are told by the injection of huge amounts of carbon dioxide into the atmosphere by the burning of fossil fuels.

        In the last century, radioactivity was discovered and explored. Fierce weapons of enormous destructive potential threaten human civilization. Reactors were designed and put into service to provide electrical energy. A great deal of resources and technology were dedicated to boiling water for steam turbines. Again, destruction of the landscape and pollution of the environment have been a result of the use of nuclear power. In addition, there is a danger of terrorist attacks on nuclear installation and nuclear accidents.

         There is now a push to develop sustainable sources of energy that do not lead to environmental devastation, pollution, scarce supplies and threats of terrorism. Wind, solar, geothermal and tidal energy systems have been developed. The primary argument against their widespread use is that they are not efficient enough or cheap enough to solve our energy needs. The counter point has been made that if the fossil fuel and nuclear industries did not receive huge government subsidies and tax break, the alternative energy sources might already be competitive in price.

        In addition, it has been pointed out that if vehicles were more efficient in miles per gallon and if buildings were better insulated, there would be a smaller need for new energy supplies. An additional benefit would be the creation of millions of new and badly needed jobs.

        There is an argument being made that nuclear energy is the best alternative to a continued reliance on fossil fuels. Issues such as reduce carbon dioxide emissions and reduction of other types of pollution as well as reduced dependencies on diminishing world oil supplies are being discussed.

         In future posts, I will discuss the pros and cons for nuclear energy and try to bring some clarity to the current discussion.

The original energy source:

          Southern California Edison (SCE) owns and operates the San Onofre Nuclear Generating Station one the Pacific Coast between Los Angeles and San Diego. The station is located next to the Cristianitos fault which is listed as inactive. Around 7.4 million people live within 50 miles of the plant.

          The Unit 1 reactor was a first generation pressurized water reactor that came online in 1967. It was decommissioned in 1992 and dismantled. It is now used to store spent fuel rods.

          The Unit 2 and Unit 3 reactors are also pressurized water reactors. They were commissioned in 1982 and their licenses are set to expire in 2022 giving them 40 year life spans.

           There have been technical problems at the plant over the years of operation. In 2008, the plant received multiple citations for such issues as failed emergency generators, improperly wired battery systems, and falsified fire safety records. A review in 2011 suggested that there had not been sufficient improvement in the area of human performance. Many anti-nuclear protests have been held at the station.

          In January 2012, a break in a pipe that carries radioactive water for the Unit 3 reactor resulted in the release of a small amount of radioactive steam. SCE stated at the time that the radiation that escaped posed no threat to the workers at the plant of people who lived nearby.

          When the steam pipes for the Unit 3 reactor were examined, it was found that they had sustained unexpected damage and the Unit 3 reactor was then shut down.

           The Unit 2 reactor was shut down for maintenance in January and it was found that many of the tubes were also worn but not as seriously as the piping of the Unit 3 reactor. that service were found to have unusual wear.

          It was eventually determined that a faulty computer analysis program had resulted in a bad design for the steam pipes that service the four steam turbines. There will need to be a lot of work on the piping system before the reactors can be restarted but no plan has been presented for how to accomplish this work.

         The initial focus is on repairing the steam pipes for Unit 2 which have less damage than the Unit 3 pipes. No schedule has been announced for the repairs to Unit 2 and there has been no estimate of when it may be started again.

         SCE has just announced its intention to remove the fuel rods from the Unit 3 reactor and move them into storage in September. This will make repair of the piping system easier but it will also mean that the Unit 3 reactor will be off line for a longer time. Removing the fuel from the reactor will incidentally reduce the number of inspections and tests that must be performed as required by the Nuclear Regulatory Commission.

         SCE had previously announced that it is laying off part of its workforce. In view of the fact that this will leave fewer personnel to carry out necessary work, it makes sense to remove the fuel and reduce the work load at the plant.

           The adverse effects of ionizing radiation on human health have been extensively studied. I have included information about what damage radiation can do in human bodies in other posts. Recent research indicates that there may be more biological damage caused by uranium than previous thought.

          “Uranium binds strongly to DNA. This has been well known and described in the peer review literature since 1962.” (see references below) Uranium oxide is chemically similar to calcium which stabilizes the phosphate backbone of the DNA. Therefore, if uranium is in the body, it will tend to be concentrated in the DNA.

          In 2002, a study was published in the Journal of Inorganic Biochemistry, Vol. 91, Issue 1, Pages 246-252 by A.C. Miller et al in the Applied Cellular Radiobiology Department of the Armed Forces Radiobiology Research Institute. They found that depleted uranium is an efficient catalyst for causing oxidative DNA base damage as a result of it’s chemical properties. This damage is much greater than any damage caused by its weak radioactivity.

          A research project in 2005 tested the effect of uranyl acetate which is the acetate salt of uranium on mammalian cells. The research was published by Diane Stearns at Northern Arizona University in the scientific journal Mutagenesis, Vol. 20, Issue 6, page 417-423. The researchers were the first to find that there were DNA strand breaks and uranium-DNA adjuncts (compounds) formed after direct exposure to depleted uranium. This can lead to protein replication errors and cancer. They concluded that uranium could be chemically genotoxic and mutagenic and could be dangerous to health beyond usual damage due to radiation exposure.

         French researchers at the Institut de Radioprotection et de Sûreté Nucléaire, Laboratoire de Radiotoxicologie Expérimentale led by C. Darolles published an article in 2009 on depleted versus enriched uranium in Toxicology Letters, Vol. 192, Issue 3, Pages 337-348. They found that while both types of uranium could cause cancer, the greatest danger from depleted uranium was caused by its chemical properties as a toxic heavy metal. The depleted uranium altered the number of chromosomes in the cell due to improper migration of chromosomes hen the cells divided. Although different than the effect of enriched uranium, this damage can also lead to cancer.

        When considering the danger of exposure to low levels of atomized depleted uranium, it would appear that its tendency to concentrate in the DNA might pose a greater danger than just considering general body exposure to its radiation or general chemical effects of exposure to a toxic heavy metal.

References:

1. Huxley, H.E. & Zubay, G. 1961. Preferential staining of nucleic acid containing structures for electron microscopy. Biophys. Biochem. Cytol. 11: 273.
2. Constantinescu, D.G. 1974. Metachromasia through uranyl ions: a procedure for identifying the nucleic acids and nucleotides. Anal. Biochem. 62: 584-587
3. Nielsen, P.E, Hiort, C., Soennischsen, S.O., Buchardt, O., Dahl, O. & Norden, B. 1992. DNA binding and photocleavage by Uranyl VI salts. J. Am. Chem. Soc. 114: 4967-4975.

          In a recent post, Hanford 3 – New Problems,  I talked about a lump of radioactive waste that had been found between the inner and outer shells of tank AY-102. There have been many DOE funded studies of the contents of that tank. Here are some of the findings. 

          Tank AY-102 is a second generation storage tank constructed with double-shell walls. It was designed to hold liquid waste generated by processing of uranium and other activities at the Hanford site. It contains 857,000 gallons of brown sludge in a translucent yellow liquid. The temperature of the tank range in temperature between 110° and 135° degrees.

          The sludge inside the tank contains chunks of aluminum, nickel, lead, silver, copper, titanium, zinc and other common elements. In 2001, sodium hydroxide and sodium nitrate were added to the tank to prevent corrosion of the walls. The most common radioisotopes in the tank include:

          Uranium 235 and 238 are most plentiful isotopes of uranium. Nuclear fuel and nuclear weapons are developed by processing the uranium to increase the percentage of U-235 which is more radioactive. Uranium is a toxic heavy metal like lead or mercury and is poisonous to human beings. Although most uranium that is inhaled or ingested is excreted by the human body in a matter of days, a small amount will be deposited in the bones where it will stay for years where it may cause cancer.

         Plutonium 238, 239, 240 and 241 are generated by neutron absorption by nuclides such as U-238 and Np-237. It is a toxic heavy metal and poisonous to human beings. It is also highly radioactive and can cause cancer if ingested or inhaled.

         Strontium-90 chemically resembles calcium and is taken up by the bones if ingested and can cause bone cancer.

         Cesium137 is one of the primary components of the Fukushima fallout. It spreads through the soft tissue of the body and can cause a variety of cancers.

         Thorium is a naturally occurring radioactive element that has been proposed as an safer alternative to uranium for nuclear fuel because it isn’t useful for making nuclear weapons. If it is inhaled or ingested it can cause lung cancer, pancreatic cancer or bone cancer.

           Carbon-14 is present in all living beings and is not considered particularly dangerous.

           Cobalt-60 is one of the radioisotopes widely used in nuclear medicine. It can cause cancer.

          Selenium-79, technetium, antimony, neptunium-237, americium-241 and curium 243 and 244. Some of these isotopes are used in industry or medicine but have their own health dangers.

         The solid lump found in tank AY-102 between the inner and outer shells is currently being analyzed to determine exactly what it contains and where it came from. The great concern is that it may have leaked from tank AV-102. If this is the case, then the double-shelled tanks are not stable and safe for storing nuclear waste while a permanent solution is found.

Solid lump in tank AY-102:

          Nuclear reactors require a huge continuous flow of water for cooling. There are a number of problems connected to this.

       Reactors must be located near either major rivers, lakes or the sea coast in order to access water for cooling. This makes them vulnerable to floods. The Fukushima disaster in Japan was largely due to the flooding of the electrical generator rooms which had been placed in the basements of the reactor buildings in spite of warnings about flooding. A United States reactor was recently threatened by rising flood water. There is no real solution to location so reactors must be constructed in such a way to minimize the continuing threat of floods.

        Some major world rivers no longer reach the sea for part of or all of year because so much water has been taken out of the river upstream for urban needs, industrial needs and agricultural irrigation. There have already been incidences where nuclear reactors had to be shut down because the water level of the rivers providing cooling water dropped to low to cool the reactors. This situation is not going to improve as world supplies of fresh water are diminishing.

        In order to effectively cool reactors cooling water needs to be under 75° F. Due to the warming of the world’s oceans caused by global warming, the temperature of the water near a reactor in Connecticut rose above 75° F and the reactor had to be shut down until the water temperature dropped. Climate projections suggest that the temperature of ocean water will continue to rise so this might be an increasing problem for any reactors that use sea water for cooling. Once again, there is no solution to this problem.

        The intakes for cooling water near a nuclear reactor are relatively small compared to the scale of the rest of a power plant. If something blocks the flow of water into the cooling intake pipes, then the reactor would have to be shut down. One man in a small boat or on foot could easily carry enough explosives to destroy extensive sections of a reactor cooling intake system. The reactor would have to be shut down while the intake system was rebuilt. Enhancing security with fences, underwater barriers, patrols, sensors, etc. could help with this problem but would be expensive. And, any security measures can be defeated.

         These concerns about cooling water could severely impact the practicality of using nuclear energy as a reliable source for a major portion of our need for electrical power. Unfortunately, these concerns are seldom raised in the discussion of problems with the use of nuclear power. And, even more unfortunately for the proponents of nuclear energy, these problems for the most part do not have solutions.

Picture from nuclearenergyinfo.blogspot.com:

         The Hanford nuclear facility contains fifty three million gallons of high-level radioactive and chemical waste. These wastes were generated when corrosive chemicals were used to dissolve spent fuel rods to retrieve plutonium. Steel tanks in concrete pits are used to hold the waste.

         One hundred and forty nine single-shell tanks were built between 1943 and 1964. The tanks were designed to last 20 years and were never intended as a permanent storage system. The waste has been eating away at the lining of the tanks since they were filled. One third of the tanks have been eaten thought completely in places and they are leaking the waste into the environment. Twenty eight double-shell tanks were built between 1977 and 1986  to accept waste from the deteriorating single-shelled tank.

         The operators at the site monitor the conditions in the tanks and move waste from the older single-shell and double-shell tanks to twenty eight newer double-shelled tanks when required but space in the new tanks is limited. Robotic systems have been developed to handle the extremely dangerous and toxic waste but they are not always employed and workers are endangered when required to deal with the waste.

         The area between the inner and outer shells of the double-shelled tanks is called the “annulus.” Annulus is Latin for little ring. It is a term generally applied to any gap between concentric pipes.

         Recently a three foot long solid lump was discovered between the inner and outer shells of one of the double-shelled tanks designated AY-102 built 42 years ago. The tank contains 857,000 gallons recovered from one of the older single-shelled tanks that was considered unsafe. There is no

        The lump has been sampled and it contains radioactive materials indicating that it is radioactive waste. There is some confusion over where the lump came from. One idea is that it leaked through the inner shell of the tank. The other possibility is that it came from leakage from one of the older tanks that made its way into the annulus of the newer tank. There is no evidence that the outer-shell of the tank has been breached and there does not appear to be any danger of contamination of soil or ground water at this time.

         Further research is being carried out to determine exactly where the lump came from. If it turns out that the material in the lump did leak through the inner shell of the newer tank, then there is a serious problem with the project to use the newer tanks to hold the waste from the older tanks that are leaking. The new design was supposed to safely hold the waste while a permanent storage solution was perfected. If the newer tanks are also starting to leak, then the current leakage problems at Hanford do not have a solution and new efforts will have to be started to protect the environment in the Hanford area.

 Double-shell tank diagram from globalsecurity.org   

       Nickel is a chemical element with symbol Ni and atomic number of 28. It is a slivery-white transition metal. Nickel was used as early as 3500 BC as part of a nickel-iron alloy found in meteorites. Nickel was first purified and identified by Axel Fredrik Crosntedt in 1751. It was named for Nickel, a mischievous creature in German Miner mythology.

       Nickel is hard and ductile with a slow oxidation rate which makes it corrosion resistant. It readily forms alloys with other metals. Along with iron, cobalt, gadolinium, nickel is one of four elements that are ferromagnetic at room temperature. It melts at 1455° C and boils at 2913° C. Nickel forms compounds such as sulfides, sulfates, carbonates, hydroxides, carboxylates, and halides.

        Nickel has 5 stable isotopes, Ni-58, Ni-60, Ni-61, Ni-62, Ni-64, and 28 radioactive isotopes ranging in atomic weight from 48 to 78. The half-lives of the radioactive isotopes vary from greater than 200 billionths of  second for Ni-51 to 76,000 years for Ni-59. Nickel isotopes with atomic weight below 60 mainly decay by emitting a positron and becoming cobalt. Ni-52 and Ni-53 decay may include emission of a proton. Above atomic weight 60, the main decay process emits an electron and the nickel becomes copper. Ni-72 to Ni-76 isotopes may also emit a neutron when they decay.

         Most of the nickel on Earth is in the inner and outer core in combination with iron. Nickel is most commonly found in pentlandite with iron and sulfur, in millerite with sulfur, in nickeline with arsenic and in galena with arsenic and sulfur. One common ore type for nickel is laternites which include limonite also containing iron, oxygen and hydrogen and garnierite also containing magnesium silicon, oxygen, and hydrogen. Another common ore type is pentlandite also containing iron and sulfur. Australia and New Caledonia contain about 45% of the known nickel reserves in the world.

         About half of the nickel mined is used for alloying with steel because of its corrosion resistance. Another third is used for other types of alloys including alloys with precious metals. 14% is used for electroplating and 6% for miscellaneous other purposes. Nickel used to be used in coinage but this has largely disappeared. A porous form of nickel is used in fuel cells. Nickel and alloys with nickel are often used as a catalyst in industrial processes. Stable isotopes of nickel are used to produce radioactive isotopes of copper and cobalt for various uses. Ni-59 has been used to date age of meteorites and to determine the amount of extraterrestrial dust in ice and sediments. Ni-63 is used to detect explosives, in voltage regulators and surge protectors, and in electron detectors for gas chromatographs.

         Nickel is an important catalyst in enzymes in biological systems although this was only recognized in the 1970s. Nickel can trigger allergic reactions in the skin of some individuals. Some compounds of nickel are toxic or carcinogenic. Irradiation of nickel-iron steel in nuclear reactors can result in the creation of Ni-63 which can accumulate in the food chain if released in a nuclear accident and pose a threat to people who consume the contaminated food.

 

          Krypton is a chemical element with symbol Kr and atomic number 36. Krypton is a colorless, odorless, tasteless gas. It was discovered by the Scottish chemist Sir William Ramsey in 1898. He discovered a series of noble gases by examining the residue left over from evaporating liquefied air.

           Krypton is one of the noble gases in Group 18 of the periodic table along with helium, neon, argon, xenon and radon. Because their outer shell of electrons is full, the nobles gases are very non-reactive and form few compounds with other elements. The melting point and boiling point of krypton are very close at -157° C and -153° C.

            Krypton has 33 known isotopes that vary in atomic weight from 69 to 101. There are 6 stable isotopes and 27 radioactive isotopes.. Kr-83,84,85,and 86 are fission products produced by uranium decay. Small amounts of some krypton isotopes are generated by cosmic rays hitting the atmosphere. The radioisotopes have half-lives that vary from 154 billionths of a second for Kr-83m1 to 225,000 years for Kr-81. Most of the isotopes of krypton are short lived The primary decay mode of isotopes lighter than atomic weight 82 is emission of a positron (anti-electron)  to become bromine. Above atomic weight 84, krypton decay emits an electron to become rubidium.  Kr-71 and Kr-73 emit protons is a small number of decays and become selenium. Metastable states of Kr-83 and Kr-85 emit gamma rays when they decay. A few krypton isotopes emit gamma rays when they decay. Kr-92, Kr-93, Kr-94, Kr-97 and Kr-101 emit neutrons during decay.

           Krypton is present on Earth mainly as a minor constituent of the atmosphere. It is also present in gas emitted from underwater thermal vents and from volcanoes. Krypton is the second rarest stable element on Earth.

          Krypton is used to make bright white lights for photography. Powerful lasers have been developed utilizing krypton. Krypton-81 can be used to date old groundwater up to 800,000 years old. Krypton-83 is used in magnetic resonance imaging of respiratory system.  It may also be useful in computer tomography imaging in a mixture of gases including xenon. Krypton-85 with a half-life of about 10 years is used indicator lights in home appliances and consumer electronics, to gauge thickness of plastics, sheet metal, rubber and paper, to measure dust and pollutant levels, to detect explosives, in voltage regulators and surge protectors, and in laboratory gas chromatography equipment. Kr-85 is released when nuclear fuel rods are reprocessed and can be used to detect clandestine reprocessing plants.

          Krypton has no known biological function and is considered harmless with regard to health. Krypton could cause asphyxiation if present in sufficient quantities to displace oxygen in the air being breathed. The radioisotopes are very short lived and their beta emission are easily blocked.  

Wicked Lasers S3 krypton laser:

 

           Promethium is a chemical element with the symbol Pm and atomic number 61. A gap in the periodic table was pointed out between neodymium at 60 and samarium at 62 by Bohuslav Brauner. After two false claims of discovery in 1926, in 1938 a few atoms of promethium were created but intentional production and chemical proof did not happen until 1945 at Ohio State University when promethium was extracted from irradiated uranium fuel. A sample of the metal was only produced in 1963. Promethium was named for “Prometheus,” the Titan in Greek mythology who stole fire from the god and gave it to humanity.

            Promethium is a metallic member of the cerium group of the lanthanide series. It forms salts with oxygen, water, chloride, nitrogen and sulfur.

           Promethium has no stable isotopes; all of its thirty eight isotopes are radioactive. They vary in atomic weight from 126 to 163. They have half-lives that range from around 200 billionths of a second for Pm-129 to 17.7 years for Pm-145. Most of the isotopes of promethium decay by emission of positrons (anti-electrons). Pm-145 also emits protons.

           Promethium is extremely rare in nature, minute quantities being produced in uranium ores by the spontaneous fission of uranium-238. This process has contributed about half a kilogram of promethium to the curst of the Earth. Pm-150 can be produced by rare beta decay of neodymium and europium decay can produce Pm-147 via an alpha particle. Europium decay has produced about 12 grams of promethium in the history of the Earth. Promethium has been found in the spectra of some stars.

            Promethium-147 is the only isotope of promethium that has industrial applications. It is produced by bombardment of unranium-235 with thermal neutrons, bombardment of uranium-238 with fast neutrons to trigger fast fission, and by decay of artificially produced neodymium-146. Pm-147 has a relatively long half-life with radiation that has a shallow penetration and it produces no gamma rays. Glowing hands and numbers for watches and gauges contain a phosphor activated by Pm-147 which causes it to emits light. Because beta emission does not cause the phosphor to age, such applications have years of stable light release. Atomic batteries utilize a sandwich of semiconductor material and Pm0147 and has about a 5 year useful lifespan. It is also used in batteries that convert light to electricity for use in watches, calculators, radios, etc. Pm-147 is used as a starter in the new compact fluorescent lamps. It can also be used to measure the thickness of materials such as plastic, sheet metal, rubber, textiles and paper. It is used in electric blanket thermostats.

          Promethium has no biological function but it is dangerous to living systems due to x-rays emitted during beta decay. Sealed devices containing promethium are safe but if the seal is broken, precautions should be taken when handling the device.

Seiko watches with promethium:

          Californium is a chemical element with the symbol Cf and atomic number 98. It is a silvery white actinide metal element that was first synthesized by bombardment of curium with alpha particles by a team at the University of California, Berkeley in 1950 and named for the state of California.

          Californium is melting point of 900° C and a boiling point of 1745° C. It is a soft malleable metal that is easily cut with a knife. It can form alloys with lanthanide metals. When heated, it reacts with hydrogen, nitrogen and oxygen. It forms salts with nitrogen, and sulfur as wells as the halogen family of elements which include fluorine, chlorine,  bromine, iodine, and astatine.  

            Californium has no stable isotopes. All of its 20 isotopes are radioactive. They vary in atomic weight from 237 to 256 with half-lives ranging from 45 millionths of a second to Cf-251with a half-life of 900 years. Cf-251 and Cf-252 emit gamma radiation. Most isotopes of californium decay by emission of alpha particles to curium or by emission of beta particles to berkelium. A few isotopes can decay to fermium and einsteinium.

           Californium is the heaviest element that exists in nature. It is generated by neutron capture and beta decay in rich deposits of uranium ore. It is not very soluble in water and will be present in much larger quantities in soil than in water. There is a small amount of californium created by nuclear explosion and present in nuclear fallout.

           Californium-250 is produced by bombarding berkelium-249 with neutrons. Cf-251 and Cf-252 are generated by bombarding Cf-250 with neutrons. Cf-252 has many applications because it is a strong neutron emitter. One fresh microgram of californium will generate 139 million neutrons per minute. Cf-252 used to be mainly used for reactor startup but that use has declined in recent years. It is used to treat some forms of cervical and brain cancer. It is used by universities for educational purposes. It is used inline to analyze bulk materials such as coal. Neutron penetrate into various materials and can be used to image such things as thickness, integrity and other useful physical properties of nuclear fuel rods, airplane parts, and corrosion, bad welds, cracks and trapped moisture in pipelines. Neutrons moisture gauges are used in the oil industry, in gold and sliver prospecting, and to detect groundwater movement.  Californium-249 has been used to create a few atoms of ununoctium, element 118, the heaviest element ever synthesized. Bombardment of californium has also been used to synthesized other transuranic elements such as lawrencium, element 103.

          Californium has no natural biological function due to its scarcity and high radioactivity. If it enters the body through consuming food, drinking fluids or breathing air contaminated by particles of californium, about two third will be deposited in the skeleton and a quarter in the liver. Californium in the skeletal tissue can interfere with the body’s ability to produce red blood cells. Gamma radiation from Cf-251 and Cf-251can cause bone and/or liver cancer when present in the body.

Toy train with californium-252 used for calibration at Princeton Plasma Physics Laboratory: