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San Onofre Still Offline Three Weeks Later

Above: San Onofre Nuclear Generating Station

Aired 2/21/12 on KPBS Midday Edition.

GUESTS

Victor Dricks, spokesman, Nuclear Regulatory Commission

Murray Jennex, Associate Professor, SDSU, nuclear power expert

Transcript

Document

NRC Memo

NRC Memo

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The Nuclear Regulatory Commission (NRC) is recommending a follow-up inspection at San Onofre Nuclear Generating Station (SONGS) after a tube leak in its steam generator forced the shutdown of Unit 3.

In a memo dated February 16th, the NRC cites the length of time the tube was in use, just one year since installed, and that due to the "the infrequency of such events in the industry, an event follow-up focused on baseline inspection is recommended to review the licensee's response to the initial indications of the tube leak."

NRC spokesperson Victor Dricks tells Midday Edition this is "fairly routine in matters like this one," adding, "we want to make sure the licensee has taken appropriate action."

"We want to independently verify their response to the event and be assured that if the plant is going to be restarted that it's done safely."

He says inspectors from Region 4 in Arlington, Texas will do the inspection within the next week or two. Dricks says they have two resident inspectors at every nuclear power plant in the U.S.

This isn't the first time there have been problems with steam generator tubes at U.S. nuclear power plants. "There have been a lot of problems with steam generators aging and thus leaking prematurely," Dricks told KPBS Midday. "The industry and NRC have a lot of experience dealing with the issue, the industry has responded very aggressively and they have procedures that all the plant operators follow when any leaks are detected." Dricks says there are a number of theories and speculation as to what's causing the wear, but no definitive answer.

It's been three weeks since the nuclear power plant that sits just north of Oceanside, California was shutdown after the leaking tube was detected. (Unit 2 was already shutdown as part of a planned outage, so currently there is no power flowing from the plant.)

Nuclear power expert, SDSU Professor Murray Jennex previously told KPBS Midday, Southern California Edison (which runs the plant), could be losing up to a million dollars a day in lost power to customers. But because power is cheaper in the Northwest this time of year, and it's not peak season, he says they may be actually saving money. ""Hydroelecrics are running more, it may be cheaper to buy replacement power than operate the nuclear power this time of year," said Jennex.

Currently, SCE is using replacement energy, but will not elaborate on how much that's costing. However, SCE spokesperson Gil Alexander says it will not be passed onto customers "in the immediate future". San Diego Gas & Electric has 20-percent ownership of SONGS and gets 20 percent, or 430 MW, of power made by the station, according to the SDG&E website.

In an update statement, Alexander tells Midday "extensive testing is underway to understand the cause of the leak, and as soon as it is understood, plant operators will implement a repair plan."

Jennex says once the problem is found and repairs and testing are completed it will be a matter of days before the plant is back online.

Comments

Avatar image for user 'Frankie'

Frankie | February 21, 2012 at 1:47 p.m. ― 2 years, 1 month ago

I thought Maureen Cavanaugh did a good job today unraveling the complex stories about SDG&E attempts to palm off costs of the Witch Fire onto ratepayers and the ongoing shutdown of San Onofre's leaky nuclear power plant with no explanation for the mishap and no remedy or re-start in sight.

Both of these stories have or will have an impact on San Diego residents, but understanding them is elusive and beyond the public's ken. For the first time that I can recall, Maureen asked tough questions that revealed how this huge utility can afford to delay outcomes and disguise its public responsibility while protecting hefty stockholders' profits.

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Avatar image for user 'Harry_S'

Harry_S | February 22, 2012 at noon ― 2 years, 1 month ago

This was a great show for the energy providers. No critical issues were seriously addressed and the reporter did not dare to ask investigative questions. No reaction from reporter when NSC spokesperson called the radioactive leak a "little mishap." Overall, a feel-good report because everybody sounded upbeat and there is no problem a San Onofre that can't be fixed, it merely takes some time. I'm disappointed how tame the KPBS reporting has become.

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Avatar image for user 'NuclearGuru'

NuclearGuru | September 19, 2012 at 11:07 p.m. ― 1 year, 6 months ago

DAB Safety Team Nuclear Safety Concern – SONGS U2 Restart

The concern is that an un-isolable main steam line break with SONGS Unit 2 replacement steam generator multiple tube leaks or ruptures even at reduced power operations could result in releases in excess of 10 CFR Part 100 and adversely affect the health and safety of the Southern Californians within the 10-mile Emergency Planning Zone.

Safety Significance

Operating experience from in-situ pressure testing resulting in 8 tube leaks in SONGS Unit 3 replacement steam generator indicates that the potential existed for a main steam line break to significantly increase SG leakage, because resonant vibrations and fluid elastic instability of SG tubes from a secondary side blowdown could have cause increased tube leakage. Southern Californians were lucky this time because only one Unit 3 Steam Generator tube leaked, which was detected and Unit 3 was shutdown.

Consequences of such an accident scenario are significant with Unit 2 Restart even at reduced power because primary coolant could be lost to the environment through the leaking or ruptured SG tubes (Due to formation of localized steam voids in the superheated central portion of U-Tube bundle, a weak Anti Vibration Support System and MHI Flowering Effect) and out the break in the secondary system. Given that the secondary side opening is outside containment but not isolable, the release of radioactivity could be above 10 CFR Part 100 limits, depending upon the iodine spiking factor and the duration of blowdown. Further, the escaping coolant will not be returned to the containment sump. There is a high probability that the ECCS will successfully mitigate a LOCA during the injection phase (Hope it works and SONGS has adequately maintained and frequently tested the ECCS Systems). However, when the refueling water storage tank (RWST) is depleted, it may not be possible to use the recirculation mode (Hope it does not happen), possibly resulting in core damage. Because the release path is open to the environment outside of the containment, the release of radioactivity from the postulated core damage event could have significant risk impacts.

The issue also includes the safety concerns of increased risk from degraded SONGS operator performance because of environmental conditions that can occur during the event. DAB Safety Team concludes that this is a significant nuclear safety issue and needs to be addressed by SCE by benchmarking Other World Wide Nuclear Utilities and Manufacturers in the Unit 2 Restart Plan.

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Avatar image for user 'NuclearGuru'

NuclearGuru | September 20, 2012 at 5:14 p.m. ― 1 year, 6 months ago

Part 1 - Posted on the US NRC Blog by DAB Safety Team
September 20, 2012 at 11:49 am
Your comment is awaiting moderation.

September 20, 2012

Dear Mr. Elmo E. Collins, Jr.

DAB Safety Team concern is that an un-isolable main steam line break with SONGS Unit 2 replacement steam generator multiple tube leaks or ruptures even at reduced power operations could result in releases in excess of 10 CFR Part 100 and adversely affect the health and safety of the Southern Californians within the 10-mile Emergency Planning Zone.

SAFETY SIGNIFICANCE

Operating experience from in-situ pressure testing resulting in the failure of 8 Alloy 690 TT tubes in SONGS Unit 3 replacement steam generator (Unprecedented experience with Alloy 690 TT Tubes failures in the World Nuclear Power Plant Operating History) indicates that the potential exists (with the type of recent 6.5 magnitude earthquake experienced in Mexico) for a postulated main steam line break to occur and significantly increase SG leakage, because resonant, flow-induced turbulent vibrations and fluid elastic instability conditions can cause increased tube leakage and the resulting high pressure jets from the leaking tubes can impinge on other damaged tubes and lead to cascading tube ruptures.

Consequences of such an accident scenario are significant with Unit 2 Restart even at reduced power because primary coolant could be lost to the environment through the leaking or ruptured SG tubes (Due to formation of localized steam voids in the superheated central portion of U-Tube bundle, a weak Anti Vibration Support System and MHI Flowering Effect) and out the break in the secondary system. Given that the secondary side opening is outside containment but not isolable, the release of radioactivity could be above 10 CFR Part 100 limits, depending upon the iodine spiking factor and the duration of blowdown. Further, the escaping coolant will not be returned to the containment sump. There is a high probability that the ECCS will successfully mitigate a LOCA during the injection phase (Hope it works and SONGS has adequately maintained and frequently tested the ECCS Systems). However, when the refueling water storage tank (RWST) is depleted, it may not be possible to use the recirculation mode (Hope it does not happen), possibly resulting in core damage. Because the release path is open to the environment outside of the containment, the release of radioactivity from the postulated core damage event could have significant risk impacts.

Continued on Part 2

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Avatar image for user 'NuclearGuru'

NuclearGuru | September 20, 2012 at 5:15 p.m. ― 1 year, 6 months ago

Part 2 - Posted on the US NRC Blog by DAB Safety Team
September 20, 2012 at 11:49 am
Your comment is awaiting moderation.

The issue also includes the safety concerns of increased risks from degraded SONGS operator performance (e.g., because of environmental conditions, confusing and convoluted mind boggling operating and emergency plan procedures, control room disruptions, communication errors between the control room operating crew and the field staff, etc.) that can occur simultaneously during the event. Without new published industry or analyzed information available for this type of Scenario Specifics to SONGS, DAB Safety Team concludes that this is a significant nuclear safety issue and needs to be addressed by MHI benchmarking Other World Wide Nuclear Utilities and Manufacturers in the Unit 2 Restart Plan.

1. The first question is, whether any of the Vendors on the SONGS Team have the Video Cameras/Other technology to determine the gaps between the inner most U-Tubes and Anti-Vibration Bars.

2. The second question is, if the Unit 2 is running at 70% reduced power, whether any of the Vendors can install remote camera/sensors all around the U-tube bundle in the high pressure, high steam-water environment, so that the Control Room Operators can detect the excessive vibrations via remote video cameras/alarms of the inner most U-Tubes and Anti-Vibration Bars and take appropriate actions to trip the reactor and initiate a controlled plant shutdown to minimize the risk for the public by stopping a radiological accident in progress.

Your urgent response along With the SCE Unit 2 Restart Plan & MHI Root cause Evaluation in accordance with President Obama’s Open Government Initiative and NRC Open and Transparent Policy is highly appreciated. A Copy of this email will be forwarded to Senator Barbara Boxer for her Files.

Thanks
DAB Safety Team

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Avatar image for user 'NuclearGuru'

NuclearGuru | September 20, 2012 at 6:04 p.m. ― 1 year, 6 months ago


****************************************************
Honorable Senator Boxer,
The above information Posted on the US NRC Blog by DAB Safety Team is for your files and future action.
Sincerely
Thanks
DAB Safety Team (Real name known to Senator Boxer)
******************************************************
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