Table of Contents
How does a very high temperature reactor work?
The VHTR can produce hydrogen from only heat and water by using thermochemical processes (such as the sulfur-iodine (S-I) process or the hybrid sulfur process), high temperature steam electrolysis (HTSE), or from heat, water, and natural gas by applying the steam reformer technology.
How does a high temperature gas-cooled reactor work?
The high-temperature gas-cooled reactors (HTGR) use helium gas at about 800 °C and 5 MPa (685 psi) as the primary coolant, graphite as the neutron moderator and fuel element structural material, and coated (Th-U) carbide or oxide fuel particles dispersed in a graphite matrix as the fuel.
What is the normal temperature of a nuclear reactor?
Then, at high temperature, it flows out. Here is another important part of reactor technology: The temperature reached in a nuclear reactor is in the range of 300 degrees Celsius. This is higher than the usual boiling point of water, 100 degrees.
How do you cool a reactor?
The approach to cooling is very simple: push water past the nuclear core and carry the heat somewhere else. The chain reaction that actually runs the reactor can be shut off in a matter of seconds. What’s left over in the core, the radioactive material, will continue to give off heat for a long time.
Why is high-temperature gas cooled reactor safer?
Because the possibility of massive fuel degradation is physically eliminated, almost all the fission products are retained inside the coating of TRISO particle in normal operation and accident condition. The failure rate of TRISO particle is very low for all accident conditions.
Why do nuclear reactors get hot?
Nuclear reactors are the heart of a nuclear power plant. They contain and control nuclear chain reactions that produce heat through a physical process called fission. That heat is used to make steam that spins a turbine to create electricity.
What takes the heat away from the reactor?
The coolant: This is a liquid or gas that transfers energy from reactor to the heat exchanger. Also used to cool the reactor.
Why do you need to cool a reactor?
Without cooling, the boil-off would continue to drop the water level below the top of the nuclear fuel in the reactor core. As nuclear fuel was uncovered by water, it would begin heating up.
At what temperatures does a gas cooled reactor operate?
The advantage of the HTGR is that the moderator, graphite and the coolant, helium, can operate at high-temperature without reacting or deteriorating. A typical HTGR will operate at a pressure of 100 atmospheres and at a temperature of up to 900°C.
How long does a nuclear reactor stay hot?
When the uranium fuel is used up, usually after about 18 months, the spent rods are generally moved to deep pools of circulating water to cool down for about 10 years, though they remain dangerously radioactive for about 10,000 years.