The Palo Verde Generating Station (PVGS) is a nuclear power plant that is near Tonopah, Arizona. It is only forty five miles from downtown Phoenix. There are three pressurized water reactors at the PVGS that each generate fourteen hundred megawatts. This plant generates about thirty five percent of the electricity that is produced in Arizona. It provides power to Southern Arizona and Southern California. The PVGS generated more electricity than any other nuclear power plant in the U.S.
Each of the three reactors at the PVGS have two emergency backup generators which are used to keep cooling water flowing over nuclear fuel in case of an accident. If backup generators fail, nuclear fuel exposed to the air can spontaneously burst into flame and release radioactive materials.
Last December 15th, one of Unit 3’s backup generators exploded during a routine test. Arizona Public Service, the operators of the PVGS discussed repairs with the Nuclear Regulatory Commission five days after the accident. Normally, a nuclear power plant is given ten days to correct such problems before it has to shut down a reactor. The NRC gave PVGS twenty three days to repair the problem. A second extension was granted in January for an additional sixty two days before the reactor would have to be shut down. The backup generator was finally returned to service on February 9th of this year. Unit 3 operated without two backup generators for fifty seven days.
The NRC said that it decided to offer the two extensions after careful consideration of the risks. Some of the staff at the NRC disagreed strongly with the decision to grant two extensions to allow the Unit 3 reactor to keep operating. Three members of the NRC staff filed dissents with regard to the extensions.
One of the dissents was a petition requesting that the extensions be revoked. This document was released to the public by the NRC. The author of the petition said that "The NRC's action is inconsistent with the NRC mission, NRC vision, NRC safety objectives, NRC regulatory effectiveness strategies, NRC openness strategies and the principles of good regulation." The NRC denied a similar request for an extension to deal with repairs from the Donald C Cook Nuclear Plant in Lake Township, Michigan. The author said that he did not understand why one plant was denied an extension while the other plant got to two extensions. He also said "I am not sure whether the loss of revenue for the utility had any influence on the NRC decision to approve these license amendments. I did not find any safety reason for NRC to approve these license amendments."
The other two dissents were Differing Professional Opinions (DPO). The authors have not been identified by the NRC and the documents have not been released. The NRC said that the DPOs were still under review. A representative of the NRC’s Office of Public Affairs stated that "The NRC reached its technical decision regarding Palo Verde’s request separately from its consideration of the DPO. The DPO process continues at this point."
Arizona Public Service said that the decision to keep Unit 3 in operation posed no threat of radiation release or any reduction in safety. They claimed that their risk analysis showed that it would be safer to keep Unit 3 operating than shutting down the reactor which would involve moving fuel rods.
Fortunately for Arizona Public Service and the citizens of Southern Arizona, the Unit 3 backup generator was repaired before any other problems arose. There is a reason that there are deadlines for the repair of emergency equipment at a nuclear power plant. I would prefer that the NRC follow their own regulations.
