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Geiger Readings for November 28, 2013
Ambient office = 55 nanosieverts per hourAmbient outside = 60 nanosieverts per hourSoil exposed to rain water = 55 nanosieverts per hourBartlett pear from Top Foods = 79 nanosieverts per hourTap water = 91 nanosieverts per hourFiltered water = 79 nanosieverts per hour
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Nuclear Reactors 89 – NASA Halts Work on New Radioisotope Generator
I have blogged before about NASA and concerns about their supply of radioisotopes used to power spacecraft. NASA has just announced that it will halt work on the Advanced Stirling Radioisotope Generator (ASRG), a new nuclear generator intended for the next generation of space probes. It was intended to replace the Multi-Mission Radioisotope Generator (MMRTG) that has been the power source of the U.S. space exploration program for decades. Basic research and development on the ASRG will be transferred from the U.S. Department of Energy to the Glenn Research Center. Budget constraints were cited by NASA as the reason for the change. NASA will continue to utilize the MMRTG for future probes.
The MMRTGs contains about ten and a half pounds of PU-238 and generates around one hundred and twenty five watts of electricity at the start of its life. The more efficient ASRG uses about two and a half pounds of PU-238 to generate one hundred and forty watts of electricity when first put into service. PU-238 has a half life of eighty seven years. With a projected mission time of about fourteen years, both generators are able to provide needed power for the whole mission. The ASRGs are about four times as efficient as the MMRTGs which means that four times as many probes could be launched for the same amount of PU-238 if the probes were powered by ASRGs.
NASA says they have sufficient plutonium-238 for the near future but it is estimated that NASA only has enough PU-238 for one more big mission which may be the Mars mission planned for 2020. The U.S. is going to restart production of PU -238 which was halted in 1989. However, only two to three pounds of PU -238 will be produced each year. The New Horizon mission to Pluto required about twenty four pounds of PU-238. It would take about ten years to produce that much PU-238 with the current projected production levels. This would mean that big space probes could only be launched about once a decade. NASA had to purchase PU-238 from the Russians for the recent Curiosity Mars mission.
On the other hand, a Jupiter mission slated for 2016 will not have a nuclear power generator on board. Due to the great distance from the sun to Jupiter, three huge solar panels will be used to power the probe. Without nuclear power generators, U.S. exploration of the outer solar system will be impossible. This may prevent the Europa mission or the Titan lander mission from being carried out.
Only the U.S. space program has launched missions to the outer solar system. Unless something changes, it is likely that missions to the outer solar system will be few and far between. This would be a serious blow to the exploration of the solar system. If you care about the U.S. space program, write to your Congressmen and the President urging the production of more PU-238 and the resurrection of ASRG manufacture. The Planetary Society is also a good place to register support for the future of the U.S. space program.
Diagram of the Advanced Stirling Radioisotope Generator:
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Geiger Readings for November 27, 2013
Ambient office = 93 nanosieverts per hourAmbient outside = 85 nanosieverts per hourSoil exposed to rain water = 86 nanosieverts per hourHass avacado from Top Foods = 59 nanosieverts per hourTap water = 78 nanosieverts per hourFiltered water = 56 nanosieverts per hour -
Nuclear Reactors 88 – US DoE Promotes Small Modular Reactors
Today I am going to discuss the promotion of nuclear power by the United States Department of Energy (USDOE). The U.S. Secretary of Energy Moniz is currently advocating for the use of nuclear power as a clean CO2 free energy source for industrial operations. This suggestion for expansion of nuclear power beyond commerical urban power generation is a welcome boost for the U.S. nuclear industry.
Monitz spoke at the Future of Advanced Nuclear Technologies conference about what are referred to as “fouth generation” nuclear reactors, especially the small modular reactors (SMR), that are currently under development. They are supposed to be simpler, easier to build, safer and even portable alternatives to today’s giant power reactors. They are being designed to operate at higher temperature than standard power reactors. Some of the uses being proposed are “process heat, water desalinization, hydrogen production, petroleum production and refining.”
The US DOE is in the process of doling out the next portion of its four hundred and fifty two million dollar grant program for the development of SMRs. It is hoped that these SMRs can be built on an assembly line and moved to the location where they will be used. There are several companies competing for the grant money including General Atomics, X-Energy, NuScale and Westinghouse. Many of the proposed designs are supposed to be able to operate between six hundred degrees and nine hundred degrees Celsius, which is much higher than the operating temperature of the current nuclear power reactors. Such high temperature reactors could also generate electricity at a lower cost than conventional reactors.
The Chinese are leading the way in the development of next generation nuclear reactors such as molten salt and pebble bed reactors. They have stated their intention to use such reactors for “hydrogen production, gasifying coal, methanol production and other industrial uses.” China hopes to have a two megawatt pilot pebble bed reactor by 2015 and a one hundred megawatt pebble bed reactor by 2024. Considering the agressive Chinese reactor construction program currently underway, it appears that they are not devoting major resources to the new type of reactors or they have not finished research and development of the new designs.
The Obama Administration states that nuclear energy must be part of the mix of new energy sources that are intended to mitigate the climate change being caused by the CO2 being produced by the burning of fossil fuels. The new generation of reactors are also seen as a way to utilize nuclear power while not adding to the risk of the proliferation of nuclear weapons.
While I applaud the desire to find CO2 free sources of energy and to reduce the risk of nuclear proliferation, I am skeptical that the SMRs will be the cheap troublefree energy source that they are claimed to be. It has taken us decades to understand what happens in conventional nuclear reactors. There will be a similar learning curve for the new SMRs. If they are widely deployed before we understand exactly what effect the higher temperatures have on construction materials over a period of decades, it is almost guaranteed that there will be accidents and shutdowns that will make the SMRs much less attractive as a new power source.
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Radiation News Roundup November 26, 2013
The story of Fukushima should be on the front pages of every newspaper in the world. counterpunch.org
Romanian national nuclear company Nuclearelectrica has signed a letter of intent towards the development of two units at its Cernavoda nuclear power plant with China General Nuclear (CGN). world-nuclear-news.org
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Geiger Readings for November 26, 2013
Ambient office = 107 nanosieverts per hourAmbient outside = 62 nanosieverts per hourSoil exposed to rain water = 77 nanosieverts per hourRedleaf lettuce from Top Foods = 75 nanosieverts per hourTap water = 84 nanosieverts per hourFiltered water = 65 nanosieverts per hour -
Nuclear Weapons 51 – Iran Nuclear Deal Struck
I have written several blogs about the stuggle of permanent members of the U.N. Security Council have had trying to make a deal with Iran about its nuclear program. Sunday, Iran signed a six months deal with the U.N. after intense negotiations in Geneva.
Iran has agreed to limit uranium enrichment to the three and one half percent necessary for creating nuclear fuels for nuclear power reactors. They have agreed not to purchase any more enrichment centrifuges. The current Iranian stockpile of uranium enriched to twenty percent must be mixed with natural uranium to dilute it to three and one half percent so it can be used as nuclear fuel. Iran has also agreed to halt work on the new reactor at Arak that could eventually produce plutonium. Although Iran claims that the Arak reactor will be used to produce isotopes of medical use, the U.N. fears that Iran could use the facility to make nuclear weapons. All Iran nuclear facilites are to be open to daily inspections by the U.N.
In return, the permanent members of the U.N. Security Council have agree to unfreeze eight billion dollars of Iranian oil revenues in their banks. They have also agreed that some trade sanctions will be lifted and there will be no addional trade sanctions imposed on Iran during the six month duration of the deal. The U.N. members believe that this deal will lead to a permanent deal that would insure that Iran never develops nuclear weapons.
The U.S. Congress will have to ratify the agreement with Iran and there is sure to be a heated debate. Critics of the deal in the U.S. Congress say that these measures are not sufficient to stop Iran’s development of nuclear weapons. Some Congressmen are even suggesting harsher sanctions to force Iran to end its nuclear program completely.
The Israelian Prime Minister says that this deal is a big mistake. He is afraid that Iran is not sincere and that they will continue enhancing uranium for the production of nuclear weapons. Israel wanted to see all of Iranian the centrifuges destroyed. Representatives of the Israeli government are angry that they were not included in the final negotiations. Israel feels threatened by Iran and has vowed to do what ever it takes to insure that Iran never manufactures nuclear weapons. This includes the possibilty of a unilateral Israeli military strike on Iran’s nuclear facilities.
Saudi Arabia has also criticised the deal with the Iranians. They also complain that they were not included in the final negotiations. They are enemies of the Iranian regime and they feel that the failure of the United States to intervene in the Syrian civial war and the intermim deal with the Iranians indicated that the U.S. can no longer be viewed as a strong ally. They have recently announced that they intend to “go it alone” in formulating their future foreign policy.
Supporters of the Iranian deal hope that it will lead to the signing of a permanent deal in the near future. Allowing Iran to return to the international trading community would have a positive impact on Middle Eastern economic activity.
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Radiation News Roundup November 25, 2013
There are serious concerns in U.S. about Fukushima radioactive material coming to our shores. enenews.com
Pilgrim Nuclear Power Station had three violations during a routine check by the Nuclear Regulatory Commission. plymouth.patch.com
A reactor at the Chalk River site in Canada returned to service Friday, ending a supply interruption of the medical isotope molybdenum-99. nuclearstreet.com
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Geiger Readings for November 25, 2013
Ambient office = 103 nanosieverts per hourAmbient outside = 128 nanosieverts per hourSoil exposed to rain water = 133 nanosieverts per hourRed seedless grapes from Top Foods = 76 nanosieverts per hourTap water = 72 nanosieverts per hourFiltered water = 61 nanosieverts per hour