|Combustion Engineering steam generators|
are similar to this Westinghouse version
I recently blogged about how I "told you so" about the San Onofre Steam Generators: Steam Generator Thoughts and Future. I told you so. I noted that the new steam generators have problems, and I referenced my previous predictions that the SONGS plants will be restarted with lower water speeds and lower power output.
On October 9, the NRC held a public meeting near the plant. (Here's the L A Times report.) At the NRC meeting, a set of panelists expressed their views on the steam generator issues, followed by questions from the audience. One of the panelists was Ken Schultz, who is a nuclear engineer and a registered professional engineer in the state of California. Dr. Schultz has graciously allowed me to use his opening statement as a guest post. A summary of his statement might be: "Steam generator tube ruptures at San Onofre will not be a safety issue."
Remarks to NRC Pubic Meeting, Tuesday 9 October 2012 on San Onofre Steam Generator Tube Leakage
|Dr. Kenneth R Schultz, Ph.D., P.E.|
We are here to discuss the NRC’s current regulatory oversight status of SONGS. I have interacted with members of the NRC during my career and have always found them to be technically skilled, extremely conscientious and critical of all data and conclusions given to them. In my interactions with them on advanced nuclear reactor designs, they were always interested in new designs with improved safety characteristics, and encouraged their investigation. I have no doubt that the NRC staff are applying the same skills and dedication to their oversight of San Onofre.
I am concerned that the press is saying the NRC thinks this may be a long investigation. I think it’s important to keep perspective that the size of the investigation is consistent with the size of the risk. A case in point is the SONGS steam generators situation. These are clearly important pieces of equipment and cost a great deal. They appear to have been incorrectly designed and to be wearing out prematurely.
Now, everything in a nuclear power plant must be investigated from a safety perspective, but the steam generators appear to not be a serious safety issue. Based on the tiny radiation dose that resulted from the failure of the Unit 3 steam generator tube, I estimate that even if all the 515 steam generator tubes that are affected by the premature wear problem were to fail simultaneously, the radiation released to a person standing at the worst place on the site boundary for the full duration of the accident would result in a dose of less than 1 µSv. Let’s put that in perspective. Low doses of radiation are a natural part of our environment. Life on earth evolved in the constant presence of low level radiation. Every year each of us living in Southern California receives about 3,000 µSv of radiation from cosmic rays, radioactive minerals in the earth and our food, and from medical and dental x-rays. If we live at higher elevation, like Denver, we’d receive about 6,000 µSv/year. If we fly a lot we’ll get an extra 2,000 µSv/year.
So that extra µSv from a steam generator accident would be like spending less than a day in the mountains, or taking less than one airline flight. I don’t see this as a safety issue. Further, there is growing scientific evidence that low level doses of radiation are not only not harmful, but may be beneficial in stimulating the body’s cellular repair systems. Again, I don’t see the steam generator problem as a safety issue and urge the NRC to proceed with their investigation.