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Can a pebble bed reactor melt down?
X-energy , located just outside the nation’s capital in Rockville, Maryland, is working on a pebble bed, high-temperature gas-cooled reactor that the company says can’t melt down. The company’s Xe-100 reactor and specialized uranium-based pebble fuel could be available in the market as early as the late 2020s.
How safe are pebble bed reactors?
Moormann, Kemp and Li’s main concern is that because pebble bed reactors are regarded as intrinsically safe, HTR-PM has been built without a high-pressure, leak-tight containment structure to serve asbackup in case of accidental release of radioactive material, and it also does not have a redundant active cooling …
Why are pebble bed reactors safe?
Some examples of this type of reactor are claimed to be passively safe. Because the reactor is designed to handle high temperatures, it can cool by natural circulation and still survive in accident scenarios, which may raise the temperature of the reactor to 1,600 °C (2,910 °F).
How are pebble-bed reactors made?
In pebble-bed reactors, the fuel and some or all of the moderator material are mixed together and made into spherical pebbles. The pebbles are then randomly packed into a suitable vessel or bed to form the reactor core ( Fig. IV-8 ).
What is the difference between HTGR and a pebble-bed reactor?
One is the pebble-bed reactor, the other is the use of the HTGR in a Brayton cycle using a gas turbine for power generation. The first of these saw actual construction and operation. In pebble-bed reactors, the fuel and some or all of the moderator material are mixed together and made into spherical pebbles.
What are the advantages of a polypebble-bed reactor?
Pebble-bed reactors have an advantage over conventional light-water reactors in operating at higher temperatures. A technical advantage is that some designs are throttled by temperature, not by control rods.
What cools the core of a PBR reactor?
In the PBR, thousands of pebbles are amassed to create a reactor core, and are cooled by a gas, such as helium, nitrogen or carbon dioxide, that does not react chemically with the fuel elements. Other coolants such as FLiBe (molten fluoride, lithium, beryllium salt)) have also been suggested for implementation with pebble fuelled reactors.