Pump liquid salt
To continue reading this article, please exit incognito mode or log in. Visitors are allowed 3 free articles per month without a subscription , and private browsing prevents us from counting how many stories you've read. We hope you understand, and consider subscribing for unlimited online access. A small startup based in Emeryville, California, will build a pilot-scale energy storage system that could provide a cheaper, more practical way of storing large amounts of electricity and help enable the power grid accommodate large amounts of renewable energy.
Halotechnics has announced a deal with a partner to construct a one-megawatt plant that will store energy in molten salts—a technique previously used to store energy at some large solar thermal plants.
The company says it will cost half as much as battery storage, and could compete with the cheapest way of storing large amounts of electricity—pumping water up a hill and using it to drive a turbine as gravity brings it back down. Molten salt storage is less efficient than battery storage—only about 70 percent of the energy used to heat up the salts becomes electricity again, whereas batteries can be over 90 percent efficient. So Halotechnics will need to offset that inefficiency with low costs.
Energy storage is becoming ever more important as the share of variable sources of energy like solar and wind power increases. Cheaper energy storage could also make the power grid more resilient and efficient by giving utilities more flexibility in how they produce and distribute power. Experts in grid energy at the ARPA-E summit say that storage will be central to restructuring the grid in coming decades, but current approaches, such as water storage, only work in certain situations and take up too much space.
Various types of salts are good at storing heat; they can be heated until they melt, and then stored in insulated containers. When the energy is needed, the molten salts can be pumped out to release their heat through a heat exchange system.
Molten salts are being employed at solar thermal power plants to store heat from the sun during the day and then generate electricity at night. The U capture-to- fission ratio in a typical MSR neutron spectrum is an example of basic data that was improved. The effect of fissioning on the redox potential of the fuel salt was resolved.
Heat transfer coefficients measured in the MSRE agreed with conventional design calculations and did not change over the life of the reactor. Limiting oxygen in the salt proved effective, and the tendency of fission products to be dispersed from contaminated equipment during maintenance was low. Operation of the MSRE provided insights into the problem of tritium in a molten-salt reactor. One unexpected finding was shallow, inter-granular cracking in all metal surfaces exposed to the fuel salt.
The cause of the embrittlement was tellurium - a fission product generated in the fuel. This was first noted in the specimens that were removed from the core at intervals during the reactor operation. Post-operation examination of pieces of a control-rod thimble, heat-exchanger tubes and pump bowl parts revealed the ubiquity of the cracking and emphasized its importance to the MSR concept.
The crack growth was rapid enough to become a problem over the planned thirty-year life of a follow-on thorium breeder reactor. This cracking could be reduced by adding small amounts of niobium to the Hastelloy-N. After shutdown, the salt was believed to be in long-term safe storage. At low temperatures, radiolysis can free fluorine from the salt. Sampling in revealed concentrations of uranium that created a potential for a nuclear criticality accident , as well as a potentially dangerous build-up of fluorine gas — the environment above the solidified salt was approximately one atmosphere of fluorine.
The ensuing decontamination and decommissioning project was called "the most technically challenging" activity assigned to Bechtel Jacobs under its environmental management contract with the U. Department of Energy 's Oak Ridge Operations organization. Much of the high cost was caused by the unpleasant surprise of fluorine and uranium hexafluoride evolution from cold fuel salt in storage that ORNL did not defuel and store correctly, but this has now been taken into consideration in MSR design.
A potential decommissioning process has been described;  uranium is to be removed from the fuel as the hexafluoride by adding excess fluorine, and plutonium as the plutonium dioxide by adding sodium carbonate.
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Views Read Edit View history. In other projects Wikimedia Commons. This page was last edited on 14 May , at This is because the magnetic field produced by the conductor and the applied magnetic field attempt to align with each other.
A similar effect can seen between two ordinary magnets. This principle is used in an electromagnetic pump. The current is fed through a conducting liquid.
Two permanent magnets are arranged to produce a magnetic field B ap as shown in the figure. The supplied current has a current density J and the magnetic field associated with this current can be called as 'Reaction magnetic Field b rc '. The two magnetic fields B ap and b rc attempt to align with each other.