Diablo Canyon Defers Millions Of Dollars Of Maintenance

An Analysis By Fairewinds Associates, Inc for Mothers For Peace

 By the Fairewinds Crew

Credit: MARK RALSTON/AFP/Getty Images

Credit: MARK RALSTON/AFP/Getty Images

Deferring maintenance of critical energy infrastructure can lead to death and devastation as evidenced by two major episodes in California.

Pacific Gas & Electric (PG&E) has a history of deferring maintenance, most notably of gas pipelines that led to 8 deaths in the San Bruno suburb of San Francisco September 9, 2010, and more recently, it was PG&E’s lack of maintenance on electrical wires that likely sparked California’s deadly Camp Fire Blaze in November 2018 that led to the deaths of at least 85 people.

In 2016, Arnie Gundersen of Fairewinds Associates Inc was retained by Mothers For Peace in San Luis Obispo to analyze documents presented by PG&E regarding the condition of the Diablo Canyon Nuclear Power Plant and to write a report for the California Public Utilities Control (CPUC) assessing its current condition for continued operation. Diablo Canyon was designed, built, and operated by PG&E beginning in 1965.

Fairewinds identified numerous examples of dangerously deferred maintenance for critical mechanical portions of the Diablo Canyon atomic power plant that were submitted in Mr. Gundersen’s testimony to the CPUC on January 27th, 2017. The Fairewinds’ report was submitted today as part of a petition, endorsed by Jane Fonda, Ed Asner, as well as numerous other celebrities, academics, and activist groups, that was sent to California Governor Gavin Newsom asking that Diablo Canyon undergo rigorous safety testing to ensure it is as safe as PG&E claims.

Now that PG&E filed for bankruptcy protection on January 29th, 2019, it is likely that new cash constraints will further delay critical plant repairs. Delay of these vital repairs at Diablo Canyon further exacerbates the ongoing danger of operating an aging nuclear power plant that has severe mechanical deficiencies and is located on numerous earthquake faults.

The entirety of Fairewinds 2017 testimony is an indictment of the overall condition of that atomic station including seismic and nuclear reactor embrittlement issues as well as deferred maintenance. However, to facilitate easier access, the Fairewinds Crew has compiled the selected portions of testimony below into a cogent synopsis of the poor condition of that nuclear station caused by PG&E deferred maintenance.  As Fairewinds stated in its 2017 CPUC testimony,

“The scientific and engineering evidence demonstrates that it is imperative that both PG&E atomic reactors are shut down in 2019… Mechanical failure is likely and there remains a finite possibility of a serious mechanical failure with a significant release of radiation from the Diablo Canyon atomic power reactors as they age further.”

Furthermore, Fairewinds Energy Education would like to emphasize Mr. Gundersen’s closing summary to the submitted report for readers of this site:

“In my professional opinion, relicensure of Diablo Canyon was doomed to fail due to its overall equipment degradation, seismic, embrittlement, and aging management issues. It would not be a prudent management decision for PG&E to expend the huge legal, engineering, and capital costs required to attempt to extend licensure at Diablo Canyon. From an engineering management point of view and in consideration of the high costs of continued operation to its ratepayers, PG&E should shut down both Diablo Canyon Unit 1 and Unit 2 in 2019.”

 

Selected Portions of

PREPARED DIRECT TESTIMONY OF ARNOLD GUNDERSEN OF

FAIREWINDS ASSOCIATES, INC., FOR SAN LUIS OBISPO MOTHERS FOR PEACE

Relating to Deferred maintenance at Diablo Canyon 

Executive Summary (Page 2 of Report)

The closure of Diablo Canyon Nuclear Power Plant (“Diablo Canyon”) has been inevitable for years. The degraded condition and economic infeasibility of the Diablo Canyon Units 1 and 2 make it imperative for economic, safety, and environmental reasons that the reactors join the long list of atomic power plants that will permanently close during the next several years. The proposed joint agreement which allows Diablo Canyon Unit 1 to continue to operate until 2024 and Diablo Canyon Unit 2 until 2025 is not substantiated by available engineering and/or economic data produced by Pacific Gas & Electric (“PG&E”) or from published data regarding the operational longevity of any other nuclear power plant operated in the United States. The proposed shutting of the plant in 2024/2025 does not appear to be based on science and technical assessment of the condition of the plant and the best interests of ratepayers, but rather merely because 2024/2025 is the end of the operating license for the plant. The scientific and engineering evidence demonstrates that it is imperative that both PG&E atomic reactors are shut down in 2019.

iv. Likelihood of Mechanical Failures (Page 17 of Report)

As stated earlier, Diablo Canyon’s procurement of mechanical components began more than 50 years ago. Engineers explain the aging phenomenon by using what is known as the “Bathtub Curve.” 19

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The curve is a graph of failure rate according to age. The failure rate is relatively high in the beginning when “kinks” are being worked out; it flattens out during the middle life phase; and it rises again sharply in the end-of-life or at the “wear-out phase.” On average, 20 years usually marks the beginning of the wear-out phase. Diablo Canyon is in the wear-out phase of the bathtub curve.

PG&E’s Application ignores the reality of the Bathtub Curve and assumes that Diablo Canyon will operate without mishap or mechanical failure from now (2017) through 2025. Yet, an extended shutdown would force the immediate closure of Diablo Canyon well before the end of its current NRC license. Based on nuclear industry data and the degraded condition of components within the plant, it is quite likely that an extended shutdown at Diablo Canyon will occur. The seminal work on long-duration NPP outages, entitled Walking a Nuclear Tightrope: Unlearned Lessons of Year-plus Reactor Outages, was published in September 2006 by The Union of Concerned Scientists (UCS).20 In the report summary, UCS stated: 

“The Nuclear Regulatory Commission (NRC) seems to be following the scrip of the movie Groundhog Day, reliving the same bad event again and again. This event— an outage at a nuclear power plant that lasts more than a year—has happened 51 times at 41 different reactors around the United States and shows no signs of stopping.”

 (Page 20 of Report)

The considerable available body of evidence indicates that many nuclear power reactors break and are permanently out of commission well before they reach the end of their 40-year anticipated operating life. Diablo Canyon is no exception to this evidentiary trend. The evidence I have reviewed shows that an extended outage due to equipment failure at Diablo Canyon is likely before 2024. If Diablo Canyon chooses to operate beyond its 2019 refueling outage, the financial risk of failure of any component and the ensuing repair outage costs and losses should be borne by PG&E’s shareholders, and not charged to the PG&E ratepayers in California.

The risk matrix referenced in the PG&E 2017 General Rate Case prepared testimony21 indicates that a significant number of the components at Diablo Canyon are tangibly degraded and in desperate need of replacement. Specifically, PG&E has labeled 320 components as degraded, but still functioning, while 3 components have downright failed. It is important to recognize that repairing aging equipment also can be a cause for reactor failure. At San Onofre 2&3, Crystal River 3, and Arkansas Nuclear One, degraded components in the wear-out phase, as defined by the Bathtub Curve, were identified and replaced. The replacement of the old equipment caused the failure of each plant as a whole, not the original degraded components. In an attempt to improve reliability by making a replacement, the owner moved from the wear-out phase to the break-in phase, at which time each new component broke. In its risk matrix22 referenced in the PG&E 2017 General Rate Case prepared testimony,

PG&E identified major components that are degraded, including and not limited to:

  • Hydraulic shock absorbers (“snubbers”) – which are required to mitigate an earthquake,

  • Worn valves in the safety injection system that pumps water into the reactor at very high pressures,

  • Worn expansion joints in the condenser – as the condenser heats and expands, it grows and shrinks and these expansion joints accommodate that movement,

  • Degraded piping that has become too thin from flow-accelerated corrosion; this physical failure requiring replacement was identified by the Flow Accelerated Corrosion program. Pipes that have thinned from flow-accelerated corrosion have worn so thin that they unexpectedly exploded and killed nearby workers at Surry Nuclear Power Plant in Virginia and other plants in Japan, and

  • An outdated 1980s era designed analog safety instrumentation needs to be entirely replaced because spare parts are no longer available. It is meant to turn critical valves and pumps and measuring equipment for the safety system on and off, but because it still works on analog circuitry it cannot be adequately computerized.

Additionally, PG&E rates its equipment and components with a “safety risk score” for each Diablo Canyon reactor, in order to determine which aging components must be replaced first. PG&E does not have the financial resources to replace them all at once. PG&E identifies categories for the failure of these components that include:

  •  “Aging/End of Life Risk” Bathtub Curve components (22 items in need of replacement).

  • “Trip Risk” items that can cause the reactor to stop but still stay pressurized (12 items in need of replacement).

  • “Shutdown Risk” after the reactor goes offline and power drops to zero, if these components do not work, the reactor pressure will drop to zero adding stress to the embrittled reactor (36 items in need of replacement).

  • “Core frequency damage risk and Nuclear Risk” refers to risk that nuclear fuel could be damaged if these components and/or equipment breaks (6 items in need or replacement).

  • “Greater than 2% Curtailment” the power level would be dropped by 2%, so the plant would have to run at reduced power (80 items in need of replacement).

 Finally, below is a small sampling of the aging components that are significantly degraded at Diablo Canyon. Unfortunately, this list shows excessive deferred maintenance thereby indicating that imminent failure is not just a theoretical possibility, but rather a likely occurrence. A sampling of the PG&E list includes:

  •  A $35M project to “Replace Process Control Racks... The current instruments are extremely hard to troubleshoot and repair due to their 1960’s architecture.”23

  • A $2.1M project to replace the doors into the control room because the hinges on the doors are excessively worn from years of use.24

  • A $4.7M project to replace the ventilation fans in the Fuel Handling Building that have long been exposed to salt air and are in constant need of repair.25

  • A $14.7M project to “Replace Incore Thermocouples...DCPP currently has 6 inoperable thermocouples and 4 unusable shortened ones in Unit 1, and as the plant continues to age, it is expected to have more failures due to age and moisture intrusion...”26

  • A $14.0M project to Replace Main Generator Exciter Rotor ...“The exciter rotor windings and insulation are subject to the same aging process as the main generator rotors and are vulnerable to failure. These rotors are designed with an internal ground detection system that has a 7-strand wire that currently has 6 broken wires.”27

  • A $5.0M project to “Replace 480 Volt Cubicle Buckets ... DCPP has experienced multiple failures of the Cutler Hammer Citation system... Failure of the MCCB to open during over-current fault conditions can lead to extensive equipment damage and fires. All components of the 480V MCC buckets have exceeded their design life ...”28

  • A $4.3M project to “Replace 125VDC ITE Circuit Breakers ... The ITE Gould HE2 breakers installed in the 125VDC distribution system are obsolete and unreliable and need to be replaced... There have been numerous problems with these breakers in the nuclear industry. Utilities are planning to replace them since there are no replacements that can be plugged directly into their old-style electrical service panel.29

  • A $4.9M project to “Replace Lube Oil Demisters... The demisters... have degraded such that oil mist is entering various buildings and components via the HVAC system that causes continued oil fouling of adjacent equipment and occupied spaces. This also becomes a health hazard when the vapors are inhaled. These demisters are original equipment, beyond useful service life and must be replaced.”30

This lengthy list provided by PG&E details the possibility of several major equipment failures, including the main generator stator, which is an extraordinarily large and expensive electrical generating component.

(Page 24 of Report)

As atomic power reactors age around the globe, these types of component malfunctions and replacements have proven to be systemic and costly, further reducing the operational reliability of old plants like Diablo Canyon as the cost to ratepayers increases with the continuous maintenance required to operate such an antiquated behemoth. Even in the best case with no serious mechanical failures, aging will inevitably cause increased costs; this technology has repeatedly shown itself to be uneconomical. Mechanical failure is likely and there remains a finite possibility of a serious mechanical failure with a significant release of radiation from the Diablo Canyon atomic power reactors as they age further.

 

E. Conclusion:

  1. It is more prudent that the California Public Utilities Commission permanently close Diablo Canyon as early as 2019 due to the magnified probability of equipment failures and the very real risk of earthquake damage.

  2. An extended outage due to equipment failure at Diablo Canyon before 2024 is likely. If Diablo Canyon chooses to operate beyond its 2019 refueling outage, the financial risk for failure of any component and the ensuing repair outage costs and losses should be borne by PG&E’s shareholders, and not charged to the PG&E ratepayers in California.

  3. In my professional opinion, relicensure of Diablo Canyon was doomed to fail due to its overall equipment degradation, seismic, embrittlement, and aging management issues. It would not be a prudent management decision for PG&E to expend the huge legal, engineering, and capital costs required to attempt to extend licensure at Diablo Canyon. From an engineering management point of view and in consideration of the high costs of continued operation to its ratepayers, PG&E should shut down both Diablo Canyon Unit 1 and Unit 2 in 2019.


19 Union of Concerned Scientists, U.S. Nuclear Power Plants in the 21st Century: The Risk of a Lifetime (March2005) <http://www.ucsusa.org/nuclear-power/nuclear-power-accidents/us-nuclear-plants-in-the-21st-century -.WIkC9BjMyB4>.

20 Union of Concerned Scientists, Walking a Nuclear Tightrope: Unlearned Lessons of Year-plus Reactor Outages, (September 2006) <http://www.ucsusa.org/nuclear-power/whos-responsible-nuclear-power-safety/walking-a-nuclear-tightrope - .WHqMPLHMzLE>.

21 See PG&E Test Year 2017 General Rate Case, Application 15-09-001, Exhibit PG&E-5, pp. 2-42.

22 See Ibid

23 PG&E 2014 Test Year General Rate Case, Application 12-11-009, Exhibit PG&E-6, p. WP3-100.

24 Id. at p. WP3-108.

25 Id. at p. WP3-111.

26 Id. at p. WP3-118.

27 Id. at p. WP3-120.

28 Id. at p. WP3-121.

29 Id. at p. WP3-122.

30 Id. at p. WP3-128.