The Truth About Nuclear Power - Part Ten

Subtitle: Nuclear plants require costly upgrades after 20 to 30 years

Steam generators inside containment structure
Purple-cutaway view.
source: NRC

One of the favorite arguments of the nuclear proponents is that, even though a nuclear plant costs more to build, it lasts for 60 years.  The second part of the statement is not true, although the first part is definitely true.  Equipment wears out, and must be replaced at significant cost.  As an example, the pressurized water reactors, PWR, have an expensive heat exchanger – the steam generator – that suffers tube degradation over time. see image.  NRC requirements cause these steam generators to be replaced when tube degradation reaches a certain level.  For some plants, the replacement works.  At California’s San Onofre plant – SONGS – however, four replacement steam generators failed recently very soon after startup.  The plant owner, Southern California Edison, SCE, elected to shut down the plant permanently rather than complete the steps required by the NRC to ensure the steam generators could be repaired and operate safely. 

Details of the SONGS steam generator troubles can be found at the NRC website: see link.  

The NRC described the tube degradation as “unexpected.”  Apparently, the type of tube wear and degradation is one that has never been witnessed before.   The tube wear was due to adjacent tubes rubbing against each other, and tubes rubbing against retainer bars.    The safety concern, unique to nuclear power plants using the PWR design, is a sudden loss of main steam header pressure.   In the words of the NRC, this is a main steam line break.   The reason this is a safety concern is that radioactive hot water under high pressure flows on the inside of the tubes in the steam generator.  At a somewhat lower pressure, water flows on the outside of the tubes.  The water on the outside of the tubes is heated, boils, and turns to steam (hence the name, steam generator).  The tube walls must retain their strength to prevent leaks of the radioactive water through the tubes and into the steam system.  The steam system's pipes run outside the containment building, into the steam turbine, and from there steam flows into the condenser.   With both systems operating normally, pressurized radioactive water on the inside of the tubes, and lower pressure water/steam on the outside, the tubes have an easier task in keeping the two water systems separate.  But, if a main steam line breaks, the pressure difference across the tube walls increases suddenly and dramatically.  Weak tubes would, of course, fail and send radioactive water and steam into the atmosphere.  This is unacceptable, but is a natural consequence of choosing to generate power using nuclear fission as the heat source.

Indeed, this is exactly what happened at SONGS when the new steam generators sprung a leak, radioactive water entered the steam system, and a small amount of radioactive steam was released into the atmosphere.  See link  As required, SCE shut down the plant to investigate. 

The sticking point in the order from NRC to SCE was this: “SCE will determine the causes of tube-to-tube interaction and implement actions to prevent recurrence of loss of integrity in the Unit 3 steam generator tubes while operating.”   That is a most reasonable requirement, find out what happened, and implement steps to make sure it does not happen again.  SCE, however, either could not, or would not take the time and expense to determine the causes.  Instead, SCE shut down both reactors in the plant.

It should be noted that minor tube wear is normal and expected.  Indeed, with the more than 9,000 individual tubes in one steam generator, a tube that is near failure due to excessive wear can be plugged to remove it from service.  The difference in this case was the rapid tube wear so very soon after the new steam generators were placed in service.   The original steam generators lasted not quite 30 years, as the SONGS reactors came online in 1983 and 1984, and the steam generators were replaced around 2010.  The radioactive steam leak occurred in January, 2012. 

There is much more to the story of the leaking tubes at SONGS.  As time permits, that story will be told.  It involves SCE trying to obtain an extension to the operating permit by claiming the replacement steam generators were sufficiently similar to the original equipment to qualify for "like-for-like" status, when the new steam generators were not "like-for-like."   A United States Senator became involved.  A re-licensing procedure would have been lengthy and the plant would be shut down for the duration of that procedure.   

In addition, the 2000 MW of electricity was lost to the grid, and had to be replaced somehow.  A part of that story is related at this link.  The good news is that at least 75 MW of the power must be from energy storage systems.  That will provide a significant boost to the grid-scale energy storage firms.  

Other nuclear plants also have been in the news due to tube wear and degradation, including the St. Lucie plant in Florida.  See link   Also, the Watts Bar plant has suffered tube wear and has ordered replacement steam generators.   Finally, the Davis-Besse nuclear plant in Ohio is replacing its steam generators, also.

It’s an exciting time.  How many more nuclear plants will go the way of SONGS, due to faulty replacement steam generators that have tubes wear on each other? 

Conclusion

It can be seen, then, that the nuclear power plant in California lasted a bit less than 30 years, not the 50 or 60 years as nuclear proponents claim.   Nuclear plants require costly upgrades after 20 to 30 years, but the anticipated added life does not always appear.  

Previous articles in the Truth About Nuclear Power series are found at the following links.  Additional articles will be linked as they are published. 

Part One – Nuclear Power Plants Cannot Compete

Part Two – Preposterous Power Pricing if Nuclear Power Proponents Prevail

Part Three – Nuclear Power Plants Cost Far Too Much to Construct

Part Four – Nuclear Power Plants Use Far More Fresh Water

Part Five – Cannot Simply Turn Off a Nuclear Power Plant

Part Six –  Nuclear Plants are Huge to Reduce Costs

Part Seven -- All Nuclear Grid Will Sell Less Power

Part Eight – No Benefits from Smaller Modular Nuclear Plants

Part Nine -- Nuclear Plants Require Long Construction Schedules

Part Ten - this article

Part Eleven - Following France in Nuclear Is Not The Way To Go

Part Twelve - Nuclear Plants Cannot Provide Cheap Power on Small Islands

Part Thirteen - Nuclear Plants Are Heavily Subsidized

Part Fourteen - A Few More Reasons Nuclear Cannot Compete

Part Fifteen - Nuclear Safety Compromised by Bending the Rules

Part Sixteen - Near Misses on Meltdowns Occur Every 3 Weeks

Part Seventeen - Storing Spent Fuel is Hazardous for Short or Long Term

Part Eighteen - Reprocessing Spent Fuel Is Not Safe

Part Nineteen - Nuclear Radiation Injures People and Other Living Things

Part Twenty - Chernobyl Meltdown and Explosion

Part Twenty One - Three Mile Island Unit 2 Meltdown 1979

Part Twenty Two - Fukushima The Disaster That Could Not Happen

Part Twenty Three - San Onofre Shutdown Saga

Part Twenty Four - St. Lucie Ominous Tube Wear

Part Twenty Five - Price-Anderson Act Protects Nuclear Plants Too Much

Part Twenty Six - Evacuation Plans Required at Nuclear Plants

Part Twenty Seven - Power From Nuclear Fusion

Part Twenty Eight - Thorium MSR No Better Than Uranium Process

Part Twenty Nine - High Temperature Gas Reactor Still A Dream

Part Thirty - Conclusion

Roger E. Sowell, Esq.
Marina del Rey, California

California PUC Orders Replacement Power for Shut Down Nuclear Plant

California Public Utility Commission requires two utilities in Southern California to procure power that is either renewable, demand response resources, or energy efficiency to replace that which was removed when the San Onofre Nuclear Generating Station was closed due to premature tube failure.  Also, at least 75 MW of the new power must be from storage systems.  

San Onofre Nuclear Generating Station
San Onofre, California
source: wikipedia

More on this later, as this requires some contemplation, research, and reflection.   Text of the press release follows.  (see link for press release)

FOR IMMEDIATE RELEASE PRESS RELEASE 
Media Contact: Terrie Prosper, 415.703.1366, news@cpuc.ca.gov Docket #: R.12-03-014


CPUC ACTS TO ENSURE ENERGY RELIABILITY IN SOUTHERN CALIFORNIA 

SAN FRANCISCO, March 13, 2014 - The California Public Utilities Commission (CPUC), in its 
ongoing mission to ensure safe and reliable utility service to customers, today directed Southern 
California Edison (SCE) and San Diego Gas & Electric (SDG&E) to procure energy supplies to meet 
Southern California needs, including from preferred resources (such as renewable power, Demand 
Response resources, and energy efficiency) or energy storage. 

SCE was ordered to procure between 500 and 700 megawatts (MW), and SDG&E to procure 
between 500 and 800 MW by 2022 to meet local capacity needs stemming from the retired San 
Onofre Nuclear Generating Station. 

Said Commissioner Mike Florio, who is the assigned Commissioner for the Long-Term Procurement 
Proceeding, “This groundbreaking decision begins the process of acquiring new resources to replace 
the 2,200 megawatts that the San Onofre Nuclear Generating Station would have supplied. It 
authorizes SCE and SDG&E to procure up to 1,500 megawatts of new resources, at least 600 
megawatts of which must be from California’s preferred resources, namely renewable power, 
Demand Response resources, and energy efficiency. The CPUC and the utilities will work to ensure 
going forward that preferred resources can provide not just clean energy, but the essential reliability 
services that are needed to ensure a stable and reliable grid. This will put us firmly on the path 
toward meeting California’s greenhouse gas reduction goals by eventually phasing out the use of 
fossil fuels to generate electricity.” 

Added CPUC President Michael R. Peevey, “This action helps us move forward in meeting the electricity needs of Southern California now that the San Onofre Nuclear Generating Station is 
permanently closed. Our combination of preferred resources and some more conventional generation 
will help in making a more secure energy future for Southern California consumers.” 

Said Commissioner Catherine J.K. Sandoval, “The shutdown of San Onofre was significant and 
unforeseen, but opened up opportunities for new technologies to take its place. Up to 1,500 
megawatts of the generation authorized to replace San Onofre can come from energy efficiency, 
Demand Response, renewable energy, and energy storage, in line with California’s vision for a 
healthier environment and economic sustainability. This decision provides flexibility while fulfilling 
the CPUC’s duty to ensure safe and reliable service at just and reasonable rates.” 

Said Commissioner Michael Picker, “Keeping the lights on is not just about comfort; it’s about 
safety and it’s about keeping our economy strong. The procurement plan that the CPUC adopted 
today is prudent and necessary for San Diego and south Orange County as we move forward from 
San Onofre and close many of the very old, dirty, and faltering natural gas plants in the area.” 

Today’s decision, combined with prior CPUC decisions aimed at ensuring energy supplies for 

Southern California, brings a total of 1,900 to 2,500 megawatts to the L.A. Basin from SCE, up to 60 

percent of which may come from preferred resources. SDG&E is required to procure at least 25 

percent and up to 100 percent of new local capacity from preferred resources. SCE and SDG&E are 

required to procure at least 50 megawatts and 25 megawatts, respectively, from energy storage. The 

CPUC’s actions thus far will offset the retirement of the 2,200 megawatt San Onofre Nuclear 

Generating Station and nearly 5,900 megawatts of once-through cooling plants. 

 

A previous CPUC decision determined that it was not feasible to rely solely on preferred resources to 

meet local energy needs and that conventional gas-fired resources must also be utilized in order to 

ensure reliability. The CPUC said it strongly intends to continue pursuing preferred resources to the 

greatest extent possible, but must always ensure that grid operations are not potentially compromised 

by excessive reliance on intermittent resources and resources with uncertain ability to meet need. The 

CPUC’s ongoing Resource Adequacy proceeding is exploring the ability of various preferred 

resources and energy storage to meet needs. Until that time, the CPUC must take a prudent approach to reliability, which entails a gradual increase in the level of preferred resources and energy storage 

into the resource mix to historically high levels. 

 

The proposal voted on is available at 

http://docs.cpuc.ca.gov/PublishedDocs/Published/G000/M088/K979/88979084.PDF. 

Roger E. Sowell, Esq. 
Marina del Rey, California