Sowell's Law Blog: Davis-Besse

Saturday, May 10, 2014

The Truth About Nuclear Power - Part 15

Subtitle: Nuclear Safety Compromised by Bending the Rules

This article begins the second theme of the Truth About Nuclear Power series, with the first theme being nuclear power is uneconomic, the second theme is nuclear power is

Universal sign for nuclear radiation

unsafe to operate. There are many who will immediately say that nuclear power is safe, and point to various facts to support their position. These next few articles will refute that argument and show that, not only are nuclear plants not safe, they grow more unsafe each year.

For those who have not read the articles on nuclear power being uneconomic, please see this link.

The approximately one dozen articles on nuclear safety will include (1) the relationship between plant operators and the regulatory commission, NRC, and show that safety regulations are routinely relaxed to allow the plants to continue operating without spending the funds to bring them into compliance. (2) Also, the many, many near-misses each year in nuclear power plants will be discussed. (3) The safety issues with short term, and long-term, storage of spent fuel will be a topic. (4) Safety aspects of spent fuel reprocessing will be discussed. (5) The health effects on people and other living things will be discussed. The three major nuclear disasters (to date) will be discussed, (6) Chernobyl, (7) Three Mile Island, and (8) Fukushima. (9) The near-disaster at San Onofre will be discussed, and (10) the looming disaster at St. Lucie. (11) The inherent unsafe characteristics of nuclear power plants required government shielding from liability, or subsidy, for the costs of a nuclear accident via the Price-Anderson Act. (12) Finally, the serious public impacts of evacuation and relocation after a major incident, or "extraordinary nuclear occurrence" in the language used by the Price-Anderson Act, will be the topic of an article.

Safety Rules are Bent

The NRC has been working with nuclear power plant owners to routinely weaken safety regulations, which allows the plants to continue operating, according to a 2011 investigation by AP (Associated Press). see link The plant owners argue that the safety regulations in question are overly-safe and unnecessary. Yet, many of the relaxed regulations are alarming. It is doubtful that the general public is aware of just how dangerous the plants are in the first place, and made even more unsafe by relaxing the regulations.

From the AP investigation: "Examples abound. When valves leaked, more leakage was allowed — up to 20 times the original limit. When rampant cracking caused radioactive leaks from steam generator tubing, an easier test of the tubes was devised, so plants could meet standards.

Failed cables. Busted seals. Broken nozzles, clogged screens, cracked concrete, dented containers, corroded metals and rusty underground pipes — all of these and thousands of other problems linked to aging were uncovered in the AP's yearlong investigation. And all of them could escalate dangers in the event of an accident."

The US plants were originally designed for only 40 years operation. Safety margins were used that would allow the plants to run for 40 years, and a bit more as good engineering practice. It is the "bit more" that is at issue. One example is the brittleness of the reactor vessel. That is rather an important item, as the reactor vessel contains the nuclear fuel, plus pressurized water at high temperature. The AP report states the criterion for brittleness was relaxed not once, but twice. Brittle metal in reactor vessel walls are less likely to withstand periodic pressure surges, but instead will crack. Additionally, some plants seek an operating extension beyond the original 40 years, which is a recipe for more frequent failures as the plants age well beyond their design life.

Another quote: "One 2008 NRC report blamed 70 percent of potentially serious safety problems on "degraded conditions." Some involve human factors, but many stem from equipment wear, including cracked nozzles, loose paint, electrical problems, or offline cooling components." A specific instance was burst steam generator tubes at Indian Point in 2000 that released radioactive steam into the air. Another instance cited is cracked nozzles on the reactor vessel head at Davis-Besse.

Finally, many pipes are corroded and leaking liquids into the environment. Valves are also leaking, many at rates that are above the allowable limits.

Conclusion

This, then, is the state of nuclear power plants in the US. The equipment is old, has been run hard, often at 100 percent capacity or slightly more for years on end. How does a plant run at greater than 100 percent capacity? Some equipment gets replaced with larger equipment, in a procedure known as debottlenecking, then the remaining equipment runs at greater than its design of 100 percent. Upsets occur, causing pressure variations or pressure surges. Electrical equipment degrades over time, pipes corrode, valves leak, all of which are normal and expected as process plants age. The fact is, the nuclear power plants are grinding down, quite literally in many cases. The safety factor that was there, once, is no longer there. Nuclear safety is compromised by bending the rules.

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 -- Nuclear Plants Require Costly Upgrades After 20 to 30 Years

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 - US Nuclear Plants are Heavily Subsidized

Part Fourteen - A Few More Reasons Nuclear Cannot Compete

Part 15 - this article

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

Wednesday, April 9, 2014

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?