The Diablo Canyon nuclear power plant is located on the coast of San Luis Obispo County in California. Since the closure of the San Onofre nuclear plant near San Diego because of damaging caused to piping by new turbines, Diablo Canyon has become the last nuclear power plant in California. Diablo Canyon is owned and operated by Pacific Gas & Electric. It has two nuclear power reactors. The original forty year license for one reactor runs out in 2024 and the other runs out in 2025. P G & E has not announced whether or not they will seek an extension for the licenses of the two reactors.
When the Diablo Canyon plant was constructed, it was known that there were major fault lines near the construction site. The plant was designed to be able to withstand quakes equal in intensity to what the historical record showed had happened around those faults in the past. Then, it was discovered that there was another fault called the Hosgri fault just three miles off the coast near the plant. The geological record showed that this fault had produced more powerful quakes than the other nearby faults. Modifications were ordered to the plant to take the possibility of more powerful quakes into account.
The seismic upgrades were finished in 1981 but it was later found that the contractors made a serious mistake. There were two reactors and both had to be upgraded. The reactors were based on the same design. One set of blueprints were used to make the changes to both reactor buildings. Unfortunately, the contractors failed to take into account that while the reactors were based on the same design, one of the reactors was a mirror image of the other. This meant that the changes made to the second reactor did not accomplish what they were intended to accomplish. The NRC allowed the plant to keep operating even though the mandated changes had not been successfully done.
In 2014, The Friends of the Earth filed a demand with the federal court to overturn the secret decision of the NRC to make changes to the way in which seismic risk was calculated in the PG&E operating license for Diablo Canyon. These changes made it possible for PG&E to continue to operate even though the original license provisions would have forced the NRC to revoke their license. The FoE claimed that there was criminal conspiracy between NRC and PG&E to allow PG&E to continue to operate the Diablo Canyon plant.
In addition to concerns over seismic safety, there are other problems for the PG&E operation of Diablo Canyon. This year, the California State Water Resources Control Board made the “once-through” cooling system in use at Diablo Canyon illegal because of its impact on marine wildlife. The FoE estimates that Diablo Canyon “causes 80% of all the serious harm to marine life from all of the coastal power plants” in California. If this rule is enforced for the Diablo Canyon plant, the cost to make necessary changes to the cooling system could rise to eleven billion dollars.
The California State Land Commission is currently considering whether or not to extend the leases for the structures that bring water into and discharge water from the plant. Currently, these licenses are set to expire in 2018 and 2019. The Lt. Governor of California has called for a detailed and complete environmental review of the Diablo Canyon operation before any action is take on the licenses.
Please read Part Two.
