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by Ace Hoffman
Wednesday, Aug. 29, 2012 at 2:04 PM
What went wrong at San Onofre last January is a classic tale of the abuse of power. San Onofre should be decommissioned (dismantled). It should never be allowed to restart.
August 27th, 2012
Nuclear power plants generate heat by bombarding "fissile" atoms (such as uranium-235) with neutrons. When the atoms are split, more neutrons are released, which then split other uranium atoms in a sustained "chain reaction." The heat energy released by this process is used to boil water to produce steam to turn a turbine which produces electricity.
The process is inherently dangerous, inherently dirty, and inherently very profitable -- if you don't have to pay the additional costs of: Accidents, cancers from routine releases, or the safe storage of the nuclear waste stream for thousands upon thousands of years. However, somebody will have to pay all these costs. Catastrophic, globally-impacting accidents are inevitable, as the world has seen four times in the last three decades: Three times in Fukushima and once in Chernobyl, with many "near-misses," many of which have been hidden from public scrutiny, and countless less serious -- but still very serious -- smaller accidents.
Every day a typical nuclear power plant operates, it generates about 250 pounds of "high level radioactive waste" which consists of:
* "Fission products," two of which are usually produced whenever a heavier uranium atom is split,
* "activation products," which are produced whenever a neutron is captured by a stable atom (such as in the millions of pounds of steel that are used at the plant),
* plutonium, which is created in copious quantities and can be used for making nuclear bombs, and
* "unburned" uranium ("burnup" is an industry term for nuclear fission. The nuclear fuel is not burned or chemically manipulated in any way.)
San Onofre Nuclear Generating Station really should be called San Onofre Nuclear Waste Generating and Storage Station. Currently over 1,400 tons of "used fuel" is stored on site at San Onofre. To grasp how vast a quantity that is, one has to consider the lethality of radioactive elements. A few millionths of a gram of plutonium for example, is enough to guarantee lung cancer if it ends up in someone's lungs. It can enter the lung as one "hot particle" or as millions of smaller particles. It's deadly either way.
Plutonium is approximately 200,000 times more deadly than uranium, and many fission products are even deadlier than that, pound for pound (or rather, microgram for microgram): Radioactive cesium, strontium, polonium, iodine, and many others.
Ever since January 2012 when recently-replaced steam generators at one of the two reactors at San Onofre sprung a leak, SanO hasn't been operating. It hasn't been generating waste, and it hasn't been generating electricity, either. The lights in Southern California have stayed on throughout the hot summer months, and the electricity grid is stable -- not counting the earthquakes. There is no need to restart SanO and plenty of reasons not to.
However, the utility company that owns and operates the plant is hurting for profits for its shareholders, and would desperately like to get San Onofre operating again. That may be impossible without somebody spending close to a billion dollars to repair the twin reactors. But who will spend that money? The utility would like it be the ratepayers, not the shareholders. The state regulators, the California Public Utilities Commission (CPUC), made the ratepayers pay -- and are still paying every month -- for the first set of replacement steam generators, at a cost of nearly a billion dollars. Since the almost-new parts have failed unexpectedly early, it will presumably cost about the same amount to restart the reactors again, plus the cost of replacement fuel for several years during the outage -- and plus the extra costs of not cutting so many corners and doing it right.
This is outrageous! The citizens of SoCal, one of the most beautiful places on earth, are put at great risk by San Onofre. It doesn't generate cheap power, it's the most expensive power in the world (when all the costs to society are taken into account). And it's obviously not reliable -- reliable "base load capacity" has always been a claim of the nuclear industry, even though capacity factors are rarely as high as with traditional gas, coal or oil power plants, let alone hydro power or many renewable alternatives. True, the wind doesn't blow all the time and the sun doesn't shine every day -- and lately, the rains don't even come -- but when those things do happen -- when the wind blows or the sun shines or the rains fall -- the energy sources are extremely reliable, and stored energy systems such as pumped water, flywheel, pressurized air, or even chemical processes (batteries) can give renewable energy systems virtually 100% uptime. Nuclear can NEVER achieve that; it has never even come close.
What went wrong at San Onofre last January is a classic tale of the abuse of power. It was the culminating event in a long series of missteps by the utility. Eager to replace approximately a billion dollars in parts prior to license renewal (so they could say they were ready and able to operate for another 20 years), the owner/operators redesigned crucial parts of the reactor that were failing prematurely. The parts, called steam generators, consist of nearly 10,000 very thin metal tubes inside a very large (the size of a school bus) container.
Inside the tubes is "primary coolant" directly from the reactor core. Outside the tubes (but inside the steam generator) is water which turns to steam as it rises. Both are normally closed, pressurized loops. A third open loop of sea water is used to condense the steam after it goes through the turbines. All three loops are fed by massive pumps which must continuously operate, using "offsite power". At San Onofre the pressure differential between the primary and secondary loops is about 1,000 pounds per square inch. The primary loop normally operates at about 2,200 p.s.i..
There are two steam generators for each of the two reactors at San Onofre, and all four steam generators were replaced within the last two years. All four have shown significant, unusual wear since then, and on January 31st, 2012, one of the tubes in one of the steam generators sprung a leak.
Since that day, San Onofre's owner/operators, Southern California Edison, have tried to come up with a plan to "safely" restart the reactor. Of course, they can never be operated safely, because many more things than just the steam generators can break catastrophically at a nuclear power plant, but ignoring that fact, as SCE does, SCE wants to at least run one of the reactors -- not the one that sprung a leak, that one's trashed -- at partial power, so they can make some money and, perhaps just as important to them, avoid an investigation by the CPUC of what went wrong (the CPUC has been so supportive of SCE's "need" to make a profit from San Onofre, that perhaps this was not a major concern, but it is always possible that an investigation would reveal something).
By state law, the CPUC is required to initiate an investigation after nine months of unavailability of a power source it regulates. Nine months will be October 31st for the reactor that sprang a leak, and a few weeks sooner, mid-October, for the other reactor, since it was already closed for upgrades (and refueling) at the time the other unit sprang a leak. Subsequent inspections showed all four replacement steam generators to be seriously worn and degraded.
But it's not just the premature wear that is the problem. It's the type of wear. Those nearly 10,000 tubes inside each steam generator have been vibrating uncontrollably and banging into each other in a cohesive and uniform -- and invariably very damaging -- coordinated pattern.
When the decision was made to replace the old steam generators with new ones (so that during license renewal in a few years, SCE could claim the reactors are "ship-shape") a large number of design changes were made -- at least three dozen significant changes.
The problem arose when they used a pair of computer programs to model the behavior of the fluids inside the steam generator. The incorrect mathematical calculations from one were carefully fed into the other, and everyone trusted the final computer output. It was off by approximately 300% to 400%.
In fact, much more steam was produced lower in the tubes than expected, so that the mixture of steam and water was nearly all steam at the top of the U-shaped tubes. Steam doesn't dampen vibration nearly as well as water does because it's about 30 times less dense.
Perhaps the problem could have been avoided if the steam generator replacement project had been accomplished through the appropriate regulatory channels, with public hearings about the exact design changes and a more careful scrutiny by the Nuclear Regulatory Commission.
But instead, SCE chose to present the new steam generators as "like-for-like" replacement parts, which was hardly the case, and slipped it through with minimal regulatory oversight at the federal level, where "safety" decisions are made, and even less at the state level, where rate decisions (and little else) is decided. They were given about $670 million of ratepayer money to pay for the project. Properly submitting the new design as a truly new design for full and open regulatory approval would have required many more public hearings, but SCE said they had merely "improved" the alloy of the tubes, not even mentioning the fact that the new alloy is 10% less efficient than the old, leading them to add hundreds more tubes, and to make each of the tubes a little thinner, and to pack them all a little closer together: A recipe for the end result. The NRC, never an agency to push hard against ANY utility, went along with the "like-for-like" assessment.
Where are we today? Unit 1 was closed for similar early wear problems in the steam generators in the early 1990s. Of the two remaining reactors at San Onofre, called Unit 2 and Unit 3, the one that actually leaked (Unit 3) apparently cannot be restarted at all unless the steam generators are replaced. Even SCE has all but admitted it, and "layoffs" of 730 employees, about 1/3 of their workforce, were recently announced and are expected to occur before the end of the year.
SCE has been saying for several months that they would like to restart the other reactor at reduced power. But despite much talk, SCE has still not submitted a restart plan to the NRC. They cannot seem to find the "sweet spot for SanO" wherein they can assure the NRC that they can cool the reactor with only one steam generator, should one of them fail, as happened in January. Running at reduced power is one thing, but what if something goes wrong? So SCE appears to be between a rock and hard place, although there is talk of design changes which they are making and which -- again -- will avoid full public scrutiny before being approved (and they surely will be approved) by the NRC: The new changes would avoid full public scrutiny by being considered minor changes to the current design!
There is only one logical, cost-effective, and safe solution: Keep San Onofre shut down forever. What could possibly be gained from rebuilding it and restarting it? It will just generate more waste -- 250 pounds per day per reactor. Nearly a ton per week for the two reactors combined. There still is no safe storage place for the "spent fuel" (used and very radioactive reactor cores). "Dry Casks" containing them will just keep piling up on our coastline as they do now. Meanwhile, an accident could require the PERMANENT evacuation of all of SoCal? It's not worth it to anybody -- except, and even this is now in doubt -- the shareholders of SCE and its parent company, Edison International.
In Japan, where three of the four catastrophic meltdowns mentioned in the beginning of this article occurred (at Fukushima in March, 2011), nearly every reactor has been shut down, and the public has been protesting night and day, week after week to keep them closed. They've seen first-hand what happens when a reactor melts down: People are relocated, property is lost, crops are poisoned, and health problems multiply. Farm animals were cruelly abandoned to their fate (ropes the Japanese put on calves eventually cut into their mouths and slowly killed them, if they didn't die of starvation in their pens or barns first). Pets were left to open their own cans of pet food, when people were told they would be allowed to return after a few days and to leave their pets, but now it's clear it will be many generations before anyone can return to many parts of Fukushima.
None of this had to happen, and it doesn't have to happen here. San Onofre doesn't have to become our Fukushima -- but it nearly did! If we keep SanO closed, we'll still have to worry about the spent fuel -- that's a huge problem and can also result in a catastrophic release of radioactive poisons. But at least the problem won't be growing, and at least there won't be any reactors to melt down, which are much more precarious. Time is the only thing that renders radioactive waste safe.
San Onofre should be decommissioned (dismantled). It should never be allowed to restart.
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