Testing No Cause For Concern at San Onofre

There has been some concern about testing being conducted at San Onore Nuclear Generating Station’s Unit 2 reactor, which is currently shut down. On Monday, as part of a plan by Southern California Edison (SCE) to test the plant’s auxiliary feedwater pumps, as well as other equipment, the plant was heated to normal operating temperature of about 535 degrees and normal operating pressure of 2,200 psi. Heat is being supplied to the system by running reactor coolant pumps, not the reactor. The heat forms steam in the steam generators, which is needed to test this equipment. During this testing, the reactor remains shutdown.

The licensee is required to perform this testing at the conclusion of a refueling outage. They expect to remain in this testing condition (Mode 3) for about one week, and then return the plant to cold shutdown conditions (Mode 5). During the extended shutdown of Unit 2, Southern California Edison plugged degraded tubes. As a preventive measure, several hundred additional tubes were plugged and removed from service because of their physical location at the top of the steam generators. This was to prevent further tube to tube wear during potential future operations.

On Sunday, October 21, 2012, craftsmen at the plant identified a small hydrogen leak coming from the hydrogen supply piping system on Unit 2. The craftsmen were checking for leaks by spraying soapy water on piping joints. This is a routine leakage check. A minute amount of bubbles were observed, indicating that a very low amount of hydrogen was leaking at a mechanical piping joint. The piping joint was tightened and the leak was stopped.

Hydrogen is used at electric power plants (not just nuclear power plants) for main electrical generator cooling. At San Onofre, the affected hydrogen piping that transports hydrogen to the generator on the non-nuclear side of the plant is outdoors near the turbine building. The small amount of hydrogen leaking from the mechanical joint did not pose a threat to the public or workers on site. Since it was outdoors, a significant amount of hydrogen at combustible concentrations could not accumulate in one area.

Victor Dricks
Senior Public Affairs Officer
Region IV

Author: Moderator

Public Affairs Officer for the U.S. Nuclear Regulatory Commission

19 thoughts on “Testing No Cause For Concern at San Onofre”

  1. I’ve gone ahead and added a backlink back to your web page from one of my clientele requesting it. We have used your blog URL: https://public-blog.nrc-gateway.gov/2012/10/25/testing-no-cause-for-concern-at-san-onofre/ and blog title: Testing No Cause For Concern at San Onofre | U.S. NRC Blog to assure you get the correct anchor text. If you woud like to check out where your website link has been placed, please email me at: sherrisegal@inbox.com. Thanks!

  2. According to Press Releases, Edison said it plugged six tubes in Unit 2 that had wear of better than 35 percent and plugged more than 500 other tubes preventively. The company said steam generators are built with additional tubes so they can be taken out of service, and that only 2.6 percent of the total tubes in Unit 2 were plugged. A review of the Westinghouse Operational Assessment for San Onofre Unit 2 Restart Plan Report indicates that 2 additional Active tubes in one of the Unit 2 Steam Generators had a wear rate of 28 percent, which is very close to wear of 35 percent limit for NRC plugging. Westinghouse is projecting the wear of these 2 active tubes in SG 2E089 from 28% to be ~31% by the end of 5 months assuming every thing will go as planned without any transients or MSLB. In light of SONGS Unit 3 Operating experience, and to adequately protect the Public Health & Safety from a potential nuclear accident, the projection of this number based on empirical formulas and data derived from other plants/tests is highly questionable. Furthermore, this number is too close to the NRC plugging limit of 35%. Therefore, these 2 degraded tubes present a formidable challenge to the Safe Restart of Unit 2 by making it highly vulnerable to localized steam dry-outs, 100% void fractions, fluid elastic instability, flow-induced random vibrations and cascading tube ruptures during unanticipated operational occurrences and Main Steam Line Breaks. Hence these 2 active tubes and any neighboring tubes should be plugged using the MHI Screening Criteria. By not plugging these 2 tubes and hundreds of surrounding tubes as a preventive measure, which can rupture these 2 high wear tubes due during a MSLB, Edison has not met the performance criteria specified in Appendix A, “General Design Criteria for Nuclear Power Plants,” (GDC 14, 15, 30 and 32) to 10 CFR Part 50, which establishes the fundamental regulatory requirements for the integrity of the SG tubes.

    SONGS RSGs have no in-plane protection, were designed with narrow tube pitch to diameter ratios, low tube clearances, taller tubes for more thermal heat (More Money in SCE’s Pocket), without NRC License 50.90 Amendment Approval Process, Without Public Hearings, Reluctant CPUC Approval, Opposition By SDG&E, Inadequate Industry Benchmarking, NO Research of Academic Literature on how to prevent Fluid Elastic Instability & Flow-induced Random Vibrations and no design of supports and knowledge of operational parameters to prevent potential localized steam dry-out areas. SONGS RSG design is a very unique and bad design, which is outside of the NORM of the RSGs Designs for United States, European, Spanish, Russian, Korean, Taiwanese, Indian, Chinese and Canadian Nuclear Fleet. SCE and MHI has to share the blame for this Billion Dollar Rate Payer Debacle. CPUC and NRC also believed everything SCE told them and did not use good judgment in providing independent oversight for SONGS RSG Project as required by their Charter. NRC & Atomic Safety Licensing Board really needs to follow the advice provided below before they start reviewing SCE Unit 2 Restart Plan.

    Quote No 1: A NRC Branch Chief gifted with MIT Intelligence, Intuition and a Sixth Sense said to an anonymous participant at an Industry Conference, “Sir, to resolve any complex technical problem and understand unclear regulations, you have to, ‘Read and reread in between the lines’, use, ‘Critical questioning and an investigative attitude’ and ‘Solid Teamwork & Alignment.”

    Quote No 2: Insanity: Doing the same things over and over again and expecting different results – Albert Einstein

    Observation No 1: SONGS Chronic Problem: Production Before Safety & Haste makes Waste

    Observation No 2: In Emergency Planning Space, decisions have to be Accurate and Timely. Under-conservative, rushed and profit-motivated analyses based on limited facts, biased and ambiguous operational data, untested deterministic and probabilistic risk analysis, conflicting theories and differing operational assessments of degraded equipment at even reduced power operations for 150 days with conditional monitoring along with unproven and unreliable compensatory actions represent enormous risks to public safety, the environment and our nation’s economy.

  3. Mihama Tube Rupture at TSP due to MS Pressurization was estimated > 8000 psig, which is 1.5 greater than MSLB Test Pressure of 5200 Psig “in-situ” pressure used at SONGS for structural testing of 8 failed tubes. That means SIPC calculations uses under conservative formulas for calculating burst pressures.

  4. HelpAllHurtNeverBaba will like to directly communicate with NRC Atomic Safety Licensing Board on SCE Restart Documents and other issues pertaining to what led to the failure of SONGS Units 2 & 3 Replacement Steam Generators (RSGs). I am a promoter of Safe and Reliable Nuclear Power. Since I have first hand knowledge on the subject, may be I can help ASLB on RSGs uncover the truth. Due to confidentiality, retaliation and family concerns, I can communicate via Email only or provide “Testimony under Oath” in Closed Dear ASLB Hearings. Need an Email contact with the ASLB to forward some critical documents under some kind of “Protection Clause.” Thanks

  5. Eight tube failures and the structural integrity of thousands of damaged tubes in SONGS Units 2 and 3 Replacement Steam Generators is being persistently questioned by the millions of worried Southern Californians, which has been termed by NRC as a very serious safety issue (Unprecedented damage in the history of U.S. Operating Nuclear Fleet – San Onofre Unit 3: 807 tubes plugged – WORST record! San Onofre Unit 2: 510 tubes plugged – 2nd WORST record). The pressure testing identified that the strength of eight tubes was not adequate and structural integrity might not be maintained during an accident. According to NRC AIT Report, “The eight tubes “failed” prior to reaching 5300 psi. Failure in this context means that leakage occurred in excess of the 4.5 gallons per minute pump capacity during the test, and test pressure could not be maintained.” In reality, this leakage @ > 0.5 gallons per minute of eight tubes in case of full blown eight tube ruptures due to a Main Steam Line Break would have been approximately 4800 gallons per minute, which is consistent with the industry tube rupture experience. This event also offers living proof for the very first time, that if a Main Steam Line Break accident had occurred, at least eight RSG tubes would have leaked/ruptured and potentially caused the SONGS Unit 3 reactor to Meltdown (e.g., Fukushima, Chernobyl, Three Mile Island, etc.) and due to loss of undetermined amount of radioactive core coolant inventory! This analysis is consistent with Dr. Joram Hopenfeld, Arnie Gundersen and his Industry Steam Generator Experts, SONGS Anonymous Insiders, Professor Daniel Hirsch and David Lochbaum have expressed serious doubts about Unit 2. UNIT 2 SCE Restart Reports/Operational Assessments by AREVA, SCE, Westinghouse and MHI are “Smoking Mirrors”, full of wish-lists, invalidated assumptions and are not conclusive. NRC, Westinghouse, SCE and AREVA have not been able to explain why Unit 2 suffered limited damage. MHI is indirectly saying that but are afraid from the backlash by NRC and SCE. NRC Really needs to follow the NRC’s Branch Chief’s (Gifted with MIT Intelligence, Intuition, Sixth Sense) advice regarding Critical Questioning & Investigative Attitude and review these SCE Restart Documents for accuracy, not like the 10CFR50.59 for RSGs. Haste is Waste. Please do not put Production over Safety. Insanity is doing the same thing over and over again and expecting different results. Albert Einstein. There is no value for Human life and safety. Please Use Prudence and Diligence.

  6. Thanks for reading our San Onofre Papers, I’m glad that many others are now realizing why allowing San Onofre Unit 2 to restart at any power level is DANGEROUS… Operating a nuclear reactor is risky enough but operating a nuclear reactor with highly damaged steam generators is insane! Now is the time for the NRC to just say N☢ to ANY RESTARTS at San Onofre, otherwise the public will be right in concluding that the NRC is not placing public safety before protecting Utility profits!

    The USA cannot afford a Trillion Dollar Eco-Disaster like Fukushima…………………

    BTW: You might also enjoy reading “Emergency Preparedness at San Onofre”

  7. Why is NRC so eager to help the SCE and not the public. This is a conflict of interest with His Excellency President Obama and Honorable Senator Boxer’s Open Government Inititiative. Americans do not want a repeat of Fukushima because TEPCO Got away with all the Safety Violations. This is not Japan, but America, the Greatest Democratic Institution in the world. All Public Officials in this country are accountable to ALL Americans. Removing a comment from a NRC Blog wont prevent a Nuclear Accident by starting a degraded reactor without ensuring public accountability and accountability. The American Government has to intervene to ensure that Nuclear Power is Safe for people. No Production over safety will prevail, no matter how rich or powerful SCE is. Thanks

  8. SONGS RSGS have no in-plane protection and narrow tube pitch to tube diameter ratio. That is why, 99.6% void fraction destroyed Unit 3 RSGs, ruptured 8 tubesat MSLB test conditions and damaged hundred of tubes due to localized dry-outs.. Unit 2 RSGs were operating at higher steam pressures, had a void fraction lower than 98.5% just like Plant A and did not experience fluid elastic instability in the in-plane direction. That is why Unit 2 suffered damage from out-of plane random vibrations. During a MSLB, Unit 2 U-Tube bundle will be uncovered and it will experience fluid elastic instability in the in-plane direction and experience damage worse than Unit 3. Due to steam/radiation environment, loud noises, communication problems, operator will not be able to re-prressurize the faulty SG. With A Main Steam isolation valve failure to close, you will experience what Dr. Joram Hopenfeld, Arnie Gundersen, Professor Daniel Hirsch and david Lochbaum have expressed about Unit 2. Reports by AREVA, SCE, Westinghouse and MHI are “Smoking Mirrors”, full of wish-lists, unvalidated assumptions and are not conclusive. NRC, Westinghouse, SCE and AREVA have not been able to explain why Unit 2 suffered limited damage. MHI is indirectly saying that but are afraid from the backlash by NRC and SCE. NRC Really needs to follow the NRC’s Branch Chief”s (Gifted with MIT Intelligence, Intution, Sixth Sense) advice regarding Critical Questioning & Investigative Attitude and review these SCE Restart Documents for accuracy, not like the 10CFR50.59 for RSGs. Haste is Waste. Please do not put Production over Safety. Insanity is doing the same thing over and over again and expecting different results. Albert Einstein. There is no value for Human life and safety. Please Use Prudence and Dilligence. Thanks

  9. America Promotes Democratic Institutions Throughout The world. Looks like NRC Does not care what millions of Southern Californians are saying about SCE Management & San Onofre Unsafe Unit 2 Reactor Restart, safety violations, retatilation and Other Chronic Management Issues. NRC is paid by American Taxpayers and NRC Region IV Officials are accountable to the public for their safety, unless NRC Chairman does not believe in His Excellency President Obamas’s open government intiative. NRC cannot misuse their authority, making unilateral decisions ignoring public opionion.

  10. San Onofre ALMOST Caused A Nuclear Disaster
    Fluid Elastic Instability (FEI) is a phenomenon that can occur in poorly designed Steam Generators (SG’s) due to very ‘dry’ steam (low moisture content, aka high steam void fractions) causing the SG tubes to vibrate vigorously along their length (called the in-plane direction) until they hit their neighboring tubes due to tight clearances. These forces can cause tube-to-tube ruptures, while the tight clearances between the tubes can be attributed to operating, poor design and or even manufacturing defects.

    At the end of January 2012, a radioactive leak in SONGS RSG Unit 3, resulted in an emergency shut down, the cause of which was later determined to have been fluid elastic instability (FEI >1) caused by higher vapor fractions (~99.6 %). Later 8 tubes failed their “in-situ” pressure testing and leaked with a flow > 0.5 gallons per minute at Main Steam Line Break Testing Conditions which resulted in more than 800 additional tubes having to be plugged; which is something that has never happened before in the USA. It is important to note that SCE’s poorly designed RSG’s now have more damaged and or plugged tubes than all the rest of the US reactor fleet put together and that is with only 7% of the tubes in Unit 3 and 8% of the tubes in Unit 2 having been visually inspected to date!

  11. 1. The hydrogen leak was on the electrical generator, NOT the steam generators. Hydrogen is used to cool the electrical generator stator. The hydrogen that was reported is completely unrelated to the reactor coolant system. The hydrogen that leaked is supplied for a tank of liquid hydrogen stored onsite that supplies cooling to the electrical generator.
    2/3. All steam generator tubes have been inspected over their full length using eddy current testing, which is the one of the best and most efficient ways to determine if tubes have been damaged. Eddy current testing will detect surface, as well as subsurface, damage. Normally, visual inspections are to inspect steam generator secondary side components other than the tubes and to inspect for loose/foreign parts. A secondary side visual inspection in accordance with industry guidelines was performed for SONGS Unit 2. SONGS also did a limited visual inspection of the tubes inside the tube bundle using a fiber optic devices, similar to an endoscope for diagnostic purposes in support of the root cause assessment.
    4. As described in the answer to Question 2 above, eddy current provides more complete and accurate information related to the condition of each steam generator tube. Visual inspections provide no flaw depth information and no information on flaws next to tube supports such as the tube support plates and anti-vibration bars.
    5. Visual inspections were done to provide additional information and insights into the causal analysis. Seismic loads were considered in the design of the steam generators in accordance with the plant design basis. The development of tube-plugging limits in the technical specifications reflect consideration of seismic loads. In addition, industry guidelines for condition monitoring and operational assessment include guidelines for consideration of seismic loads when determining the tech spec tube integrity performance criteria are met. For tubes with excessive tube wall wear, the tubes are often “staked or stabilized” prior to plugging to minimize any chance of a cascading effect. For SONGS Unit 2, all tubes being plugged or preventively plugged for tube-to-tube wear have stabilizers installed. In 1987 (at a US plant) and in 1991 (at a plant in Japan), there was a tube failure which resulted from a fatigue failure, with no corresponding cascading impact on surrounding tubes.

    Victor Dricks

  12. With regards of item 1, prior to the 90s, there was no real guidance, and plants were using 8 hour averages of core thermal power to run slightly above 100% during peak power, and slightly below it just after or before, so that their average was exactly 100%. After this was discovered, (I believe there were violations), but averages and the requirements changed to prevent this practice. Operators cannot knowingly or willfully raise reactor power above 100% indicated. Newer guidance (much more specific guidance) came out which allows for small fractional excursions and instabilities to allow instantaneous neutron flux or core power to exceed 100%, provided the average over set periods of time is always below 100%, and the operator can never knowingly and willfully allow power to increase past 100%, (in other words, only natural phenomena can allow an increase past 100%, and it must be promptly corrected when detected).

    Violating license power limit is very severe, it should be easy to look up enforcement actions to see if they ever did this.

    With regards to “over redline” as you call it, all nuclear plant design and safety analysis assumed the reactor was actually 2% overpower to begin with, so for power that is slightly over, there is no real impact to the plant, its equipment, or its safety analysis, but it is a decrease in the safety margin which was assumed into plant design. (In other words, thermal power in and of itself should not have affected the SGs, because plant design already assumes you are over your licensed power limit). You can also read the reports available which demonstrate that flow inelastic instability is the cause of the SG wearing.

    Tech Spec Violations without a NOED will always involve enforcement. If a safety limit is violated, it also requires a mandatory shutdown until NRC permission is received to restart the unit. I would recommend searching for and reading the standard technical specifications on the NRC website.

  13. Three more questions for Mr. Victor Dricks

    1. Has SCE ever violated their SONGS Technical Specifications, which states, “Southern California Edison Company (SCE) is authorized to operate the facility at reactor core powers levels not in excess of full power (3438 megawatts thermal) and if so for how many months and or years have they done so?

    2. If they have violated their Technical Specifications, what if anything has Region IV done about it?

    3. If unit 3 was indeed operated “over redline,” has the NRC considered this gross violation in their analysis of the root cause of Unit 3′s tube failures, and if not, why not?

  14. In regard to operational safety:

    ➢ The DAB Safety Team strongly recommends that NRC Regulations, Analyses and Computer Models be immediately revised and updated for all the rest of the US operating reactors and especially San Onofre, to address both public safety and radiological doses, which can be potentially caused by multiple tube (already degraded tubes such as SONGS) ruptures under normal operating (65-100% power) conditions with or without DBE/DBAs (Including MSLB, LOCA, LOOP, etc.).

  15. Questions for Victor Dricks
    1. The reactor coolant is highly radioactive, why did you leave that out?
    2. To date only about 15% of the tubes have been visually inspected, therefore the true
    condition of all the rest of the tubes is UNKNOWN.
    3. Why has SCE not had the rest of the tubes inspected unless they are afraid of what
    they will find?
    4. Why has the NRC not directed SCE to inspect all the tubes visually, since these RSG’s
    have more damage than ALL the rest of the US reactor “fleet” put together?
    5. Does this “testing” somehow hope to validate SCE’s poorly designed (569 Million Dollar)
    RSG’s, because it does not take into account any “Problems” like an earthquake and or
    rupture, which would cause even these plugged tubes to vibrate and or damage the
    tubes around them in an “cascade” effect that would surely lead to a nuclear incident?

    BTW: When the Hydrogen leak was reported why was the amount of radiation (if any)
    also not reported? Why should those living nearby have to wait days and or beg
    for relevant data from SCE and or the NRC on ANY LEAKAGES from San Onofre?

  16. Just for a little more information, this “testing”, is actually surveillance requirements as part of every plant’s Operating License Technical Specifications. Prior to specific mode changes for the plant (such as putting the reactor head on), or within a required timeframe, many of the emergency systems need to be proven OPERABLE. This is typical for all nuclear plants, and is not a special test or inspection, but instead is a operating license requirement as part of verifying your emergency systems function.

Comments are closed.

%d bloggers like this: