One of the major problems with achieving commercial nuclear fusion is the fact that when magnetic confinement is used to squeeze a plasma, instabilities can develop which interfere with the production of fusion. This is a problem is universal in all tokamaks which are donut-shaped experimental fusion reactors. The Princeton Plasma Physics Laboratory (PPPL) of the U.S. Department of Energy (DoE) is working on a way to control the worst of these plasma instabilities.
       The PPPL is working on what are called “tearing modes.” These are instabilities in plasma that create magnetic islands. These islands are like bubbles in a fluid. They can grow and cause disruptions that halt the fusion reaction and can actually damage the tokamaks where they occur.
       Fusion researchers in the 1980s discovered that they could inject radio-frequency (RF) waves to cause a current that would stabilize tearing modes and reduce the chance of fusion disrupting events. This is referred to as “RF current drive.” They did not know then was that small changes in the temperature of the plasma could enhance the stabilization of the plasma beyond a specific threshold of power. The PPPL is exploiting this process to improve the stability of plasmas.
       Tiny fluctuations in temperature influences the intensity of the current and how much of that current enters the magnetic islands. The interaction of the fluctuations and the amount of energy that winds up in the magnetic bubbles interact in a complex non-linear fashion.  The interaction between the fluctuations and the energy deposited in the islands can stabilize the plasma. This stabilization is less sensitive to misalignments of the injection current. The result of this process is called “RF current condensation” which refers to the increase in RF energy inside the magnetic islands that keeps the islands from growing and disrupting the plasma reaction.
       Allan Reiman is a theoretical physicist at PPPL and lead author of the paper reporting their work. He said, “The power deposition is greatly increased. When the power deposition in the island exceeds a threshold level, there is a jump in the temperature that greatly strengthens the stabilizing effect. This allows the stabilization of larger islands than previously thought possible.”
       Nat Fisch is associate director for academic affairs at PPPL and coauthor of the report. He published a paper in the 1970s which revealed how RF waves could be used to drive currents into tokamak plasmas. Reiman published a paper in 1983 that predicted that RF current drive could be utilized to stabilize tearing modes. He said, “The use of RF current drive for stabilization of tearing modes was perhaps even more crucial to the tokamak program than using these currents to confine the plasma. Hence Reiman’s 1983 paper essentially launched experimental campaigns on tokamaks worldwide to stabilize tearing modes. Significantly, in addition to predicting the stabilization of tearing modes by RF, the 1983 paper also pointed out the importance of the temperature perturbation in magnetic islands.”
        He went on to say, “We basically went back 35 years to carry that thought just a bit further by exploring the fascinating physics and larger implications of positive feedback. It turned out that these implications might now be very important to the tokamak program today.”

Ambient office  = 93 nanosieverts per hour

Ambient outside = 62 nanosieverts per hour

Soil exposed to rain water = 59 nanosieverts per hour

Yellow bell pepper  from Central Market = 102 nanosieverts per hour

Tap water = 116 nanosieverts per hour

Filter water = 111 nanosieverts per hour

       I have been blogging lately about Soviet and Russian nuclear weapons. Today, I am going to continue that theme with a post about Russian nuclear submarines.
       In the 1980s, the Soviet Union began development of a fourth-generation submarine referred to as the Borei-class which would replace the aging and obsolete Delta and Typhoon classes of submarines. The Soviet Union fell but the Russian government which followed remained committed to the Borei-class of nuclear submarines which they believed would be strong leg of their nuclear triad for decades to come.
       The Russians considered modernizing their Typhoon-class submarine fleet but abandoned the idea because of the expense. The Borei-class was based on a completely new design concept. The Russians intended the Borei-class to be smaller and lighter than the Typhoon-class while carrying more powerful weapons. At twenty-four thousand tons, the Borei-class submarines are about half of the weight of a Typhoon submarine. They are thinner than the Typhoons and can travel a little faster.
       The weapons carried by the Borei submarines are definitely more powerful than the Typhoon submarines payload. The RSM-56 “Bulava” is ballistic missile with a five hundred and fifty kiloton nuclear warhead. It has a special inertial navigation system. They were specifically designed for the Borei-class. The Typhoon-class carried R-39 Rif ballistic missiles with one hundred kiloton nuclear warheads.
       By 2006, the Russian navy had three Borei submarines in active service. In 2008, the Russian Navy announced that rest of the seven Borei submarines planned for construction by 2024 would be based on a revised design. This new Borei II design would have less noise, advanced communications technology and improved crew living quarters. There had been speculation that the Borei II’s would have twenty Bulava tube-launchers but now it appears that all of the Borei II submarines will have the same sixteen tube-launchers as the current Borei submarines in service.
       The new Borei class submarines are definitely an improvement on the old Delta and Typhoon classes. However, they do have a serious problem that may ultimately interfere with their planned construction and deployment. They are very expensive. They are about half the two-billion dollar cost of the old U.S. Ohio-class submarines but Russia has a much smaller defense budget than the U.S. And, in addition, the Russians  are involved in several major projects that are competing for their defense dollars.
        The estimates being used concerning the cost of a Borei submarine do not include the Borei II improvements. And, they do not include the costs of research and development for the Borei-class submarines. The development of the Bulava missiles was fraught with serious problems and delays.
        Military sources inside of Russia say that the next set of improvements planned for the Borei III version has been cancelled because of cost. There are also reports that the Russian Navy has halted work on the last two Borei submarine orders that were scheduled for delivery in the mid-2020s.
       Making the situation even more complex is the fact that the Russian Navy is also working on the Yasen-class submarines. The cost of the first Yasen submarine was one and a half billion dollars, more than fifty percent above the cost of each Borei submarine. The second Yasen submarine is projected to cost three billion dollars.
       Time will tell how the Russians will balance involvement in two separate and expensive submarine projects.

Ambient office  = 92 nanosieverts per hour

Ambient outside = 95 nanosieverts per hour

Soil exposed to rain water = 97 nanosieverts per hour

Crimini mushroom  from Central Market = 138 nanosieverts per hour

Tap water = 80 nanosieverts per hour

Filter water = 73 nanosieverts per hour

       The U.S. Department of Energy has just announced that it will award a contract to American Centrifuge Operating LLC (ACO), a subsidiary of Centrus Energy Corporation. The contract is for a demonstration of a method for production of high-assay low-enriched uranium (HALEU). The DoE said that ACO is the only company able to carry out the requirements of the contract.
       Current nuclear power plants burn low-enriched uranium which contains less than five percent fissile uranium-235. Many of the designs being explored for advanced nuclear reactors require the use of more highly enriched uranium with five to twenty percent uranium-235 enrichment.
      The HALEU Demonstration Program has two primary objectives. The first objective is the creation of a cascade of sixteen AC-100M centrifuges to produce nineteen and three quarters percent HALEU by October 2020. The second objective is to demonstrate that US-origin enrichment technology can produce HALEU. The DoE will be provided with a small amount of HALEU for research and development. The contract is expected to extend from January of 2019 to December of 2020. It includes an option for extension for an additional year.
       The DoE notices says that only U.S.-origin technology can be used to produce HALEU for use in any advanced civilian or defense-related reactor application. The DoE requires that the contractor be both U.S.-owned and U.S.-controlled because of “the sensitive nature regarding access to and operation of US-origin enrichment technology.”
       The AC-100M centrifuge was designed and constructed by ACO. The AC-100M is the only existing uranium enrichment technology that meets the criterion for the DoE contract. ACO and Centrus Energy both satisfy the DoE contract ownership and control criteria. ACO also has a license with the U.S. Nuclear Regulatory Commission which will allow it to meet the schedule laid out in the contract. ACO subleases a facility from the DoE at Piketon, Ohio. The facility is specifically designed for uranium enrichment.
       The NRC issued the ACO license for the construction and operation of a uranium enrichment commercial plant at Piketon in 2007. The plant was constructed, and a cascade of centrifuges was operated for three years to demonstrate the long-term reliability of the enrichment technology before commercial operation. Operation of the facility halted in 2016 because ACO was unable to secure funding to move on to commercial operation. 
      Ohio Senator Rob Portman said that the DoE will invest one hundred and fifteen million dollars in the HALEU Program over the next three years. He said that the DoE contract announcement was a “milestone” for the Piketon site. He added that “Getting Piketon back to its full potential benefits the skilled workforce here, the surrounding local economy, and strengthens national energy and defense security.”
      AOC told an interviewer that “If America wants to be competitive in supplying the next generation of nuclear reactors around the world, we need an assured, American source of high-assay, low-enriched uranium to power those reactors. We stand ready to work with the Department [of Energy] to get the proposed project under way as quickly as possible.”    
      At present, there are no facilities in the U.S. that can produce commercial quantities of HALEU. The Nuclear Energy Institute (NEI) has called for the development of national nuclear fuel cycle infrastructure in the U.S. to support the development of advanced reactors. The NEI president said, “DOE’s investment is a significant starting point in the HALEU fuel infrastructure. We appreciate [Energy] Secretary Perry’s attention to this urgent matter and look forward to working with DOE and Congress to ensure the US can compete globally to design and deploy advanced reactor technology.”

Ambient office  = 87 nanosieverts per hour

Ambient outside = 118 nanosieverts per hour

Soil exposed to rain water = 118 nanosieverts per hour

Crimini mushroom  from Central Market = 103 nanosieverts per hour

Tap water = 92 nanosieverts per hour

Filter water = 86 nanosieverts per hour

       Recently I wrote a couple of posts about esoteric tactical nuclear weapons programs in the U.K. and the old Soviet Union that were abandoned as impractical. However, some tactical nuclear weapons were built and deployed.
       In the 1950s, the Soviet Union mounted two 230mm recoilless rifles on a BTR-60 tank chassis. This system was called a “Reseda” launcher.  They were designed to fire 360mm tactical nuclear shells a distance of about three miles. But this was a rather primitive weapon and was soon abandoned.
       In the 1960s, the Soviets decided that they needed something more sophisticated in tactical nuclear weapons, so they ordered the design of a new generation of tactical nuclear launchers. “Taran” was the name given to a planned nuclear tank unit.
      During this time the Soviets developed what was called a “missile tank”. The IT-1 tank had an anti-tank guided missile launcher which served as its primary weapon instead of the usual main gun. This concept was incorporated into the Taran project to create a missile tank that was equipped to fire big tactical nukes. The Taran could also fire anti-tank guided missiles. It was mounted on the chassis of a T-64 tank. The turret was completely redesigned and contained a rocket-gun.
      The tactical nuclear projectile had a caliber of 300mm and weighted three hundred and thirty pounds. The actual warhead itself weighted about a hundred and forty pounds. The yield of the warhead was three tenths of a kiloton. Each Taran carried three of these projectiles. The technical specification for the Taran said that it had a range of about four miles but could actual fire up to seven miles. When fired in direct mode by line of sight, the projectiles should have landed within a hundred yards of the target. When fired in the indirect mode which required the projectiles to be locked onto a target, the accuracy dropped to within two hundred and fifty yards.
       By the 1970, the Soviets lost interest in the Taran. The idea that a nuclear confrontation could be restricted to the actual battlefield was replaced by the fear that any use of tactical nukes could easily escalate to all out global nuclear war. It was determined that the accuracy of the Taran was not good enough considering the small yield of the actual warhead. It would have only worked if the enemy forces were concentrated in a small area.
       The Soviet 195 tank prototype had the ability to fire 152mm artillery shells from its main gun. This means that the Object 195 should have been able to fire the 3BV3 tactical nuclear shell from its main gun. The yield of the 3BV3 is one kiloton.
       One of the current main Russian tanks, called the Armata, was probably developed partly from the Object 195 tank prototype. It has the ability to be retrofitted with a 152mm gun in the future. Although some in the Russian military question the usefulness of a nuclear tank, someday the Russian army may have their own nuclear version of the Armata.