Question 1: What do steam generator tubes have to do with safety?
Answer: (From Nuclear Power Plant Basics)
Steam generator tubes have walls thinner than a credit card to help transfer heat, but they also MUST serve as a vitally important boundary between the radioactive coolant circulating inside the tubing from the non-radioactive water/steam mixture which circulates outside the tubing in order to prevent a nuclear incident or worse a nuclear accident! A leak, crack or worse, a complete failure (rupture) of one (or more) of any of these thin tubes inside the steam generator would allow highly radioactive coolant to mix instantly with the non-radioactive water/steam mixture, which would then escape into the environment. Additionally, should a main steam line break or any number of other similar problems occur, the rapid loss of core coolant that is needed to constantly cool the radioactive fuel rods in the reactor could lead to a catastrophic meltdown of the entire radioactive reactor core, like Fukushima.
Question 2: How safe are the tubes in the 680 million dollar Unit 2 & 3 replacement steam generators at San Onofre?
A. At the June 18, 2012 NRC Region IV Augmented Inspection Team presentation, the NRC said, “Throughout the US nuclear industry, this is the first time more than one steam generator tube failed pressure testing…. Eight tubes failed. The pressure testing identified that the strength of eight tubes was not adequate and structural integrity might not be maintained during an accident… this is a serious safety issue.” Yet no major violations and/or fines were given, why not?
B. Later in the November 09, 2012 report, a portion of the NRC Region IV Augmented Inspection Team report stated, “Specifically, the Supplier shall demonstrate that its design will minimize vibration-induced tube wear or fatigue in the tube bend area of the tube bundle." The licensee did not meet Procedure ... requirements to ensure the design of the retainer bar was adequate with respect to the certified design specification. Specifically, the licensee failed to ensure that there was sufficient analytical effort in the design methodology of the anti-vibration bar assembly to support the conclusion that tube wear would not occur as a result of contact with the retainer bars due to flow-induced vibration. Yet again no major violations and/or fines were given, why not?
C. A single tube in Unit 2 was then discovered with 90% wear, far exceeding its 35% wear safety limitation, that was still in-service until Unit 2 was shut down for a scheduled refueling and Edison never even knew it! Yet again no major violations and/or fines were given, why not?
Note: Tubes hitting against their retainer bars causing wear problems are just one example of Edison's failure to meet their Certified design specifications. By not doing this, Edison violated the 10 CFR Part 50, GDC 14 and Steam Generator Tube Structural Integrity Criteria. In short, the failure of eight (8) steam generator tubes in San Onofre Unit 3 Replacement Steam Generator E-088 during “in-situ” (in place) main steam line break pressure testing should have been characterized as a RED major safety violation of Edison's licensing commitments, instead of a GREEN very minor violation and yet again no major violations and/or fines were given, why not?
Question 3: Is anyone really enforcing Public Safety at San Onofre?
Answer: Instead of performing the strict enforcement required of an Independent Regulator tasked with ensuring Public Safety, it is the DAB Safety Team’s opinion that NRC Region IV Augmented Inspection Team is helping cover up both Edison's dangerous steam generator tube design and their gross negligence. Because Region IV's investigation does not meet the NRC Chairman’s Standards, the NRC needs to investigate itself ASAP to find out why no major safety violations and/or large fines have been given out.
Want to read more, Allegation - Dangerous Safety Cover Up At San Onofre will soon be posted on the web at this link: DAB Safety Team Documents.