NRC Relicensing Old "Zombie" Nuclear Plants

mdsolar writes "In the Dec. 7 edition of The Nation, Christian Parenti details what he considers to be the real problem with nuclear power as a solution to carbon emissions in the US: Not the high cost of new nuclear power, but rather the irresponsible relicensing of existing nuclear power plants by the Nuclear Regulatory Commission. The claim is that the relicensed plants — amounting to more than half ot the 104 original 1970s-era nukes in the US — operate like zombies beyond their design lifetimes only because of lax regulation spurred by concern over carbon dioxide emissions. But these plants are actually failing, as demonstrated by a rash of accidents. And some of the ancient plants are now being allowed to operate at 120% of their designed capacity. There is a video interview with Parenti up at Democracy Now."

Comments

Considerable lack of knowledge

[fatbaldsubmariner]

I work as a plant operator at a boiling water reactor. The re-licensing of plants for an extra 20 years is based on the life span of the pressure vessel. The author is correct about neutron embrittlement. It does cause materials to fail by causing interstitial point defects in the grain structure. However, the point defects reach an equilibrium over the life of the plant. As more defects are created by collisions with neutrons, others are filled again by a collision. This has been observed through mechanical testing of test materials that are placed in high neutron flux zones in the core. These are removed and mechanically tested every 2 years. Calling these old plants 'zombies' is indicative of a serious lack of knowledge about materials, engineering and nuclear power in general. As to the horrific sounding 120% power levels that plants are running, you can thank digital technology for this extra power generation. When the plants were designed in the 60s, analog controls required tremendous safety margins to ensure save operation. Coolant flows and many other variables had a large margin of uncertainty when being measured and computed to show reactor power. With modern computers, we can get extremely precise readings on coolant flows, neutron flux, etc, which allows us to increase the power of the reactor without reducing the margin of safety we operate under.