$280M Nuke Plant Project Adds Efficiency, Safety, Officials Say

Workers will install new turbines and safer, easier-to-operate reactor heads at San Onofre this year.

The San Onofre Nuclear Generating Station is poised to embark on a $280-million project to improve efficiency and safety at the plant.

For openers, workers will install new turbines, built with more aerodynamic blades to capture more steam energy, which will improve the plant's efficiency by about 40 megawatts, or 3 percent.

That might not sound like much, but because San Onofre generates so much electricity, 3 percent is enough to power 26,000 homes.

Also set for installation this year are two reactor heads that look like inverted steel bowls with dozens of tubes sticking out. Each tube contains a rod that moves up and down among the nuclear material in the reactors. This allows the nuclear reaction to take place, producing heat to boil the water. Steam from the boiling water turns the turbines to create electricity.

The new reactor heads have better alloys and fewer welds, improving safety and reducing inspection time, said Chief Nuclear Officer Pete Dietrich.

Southern California Edison spokesman Gil Alexander said Unit 2 at the plant is now running at 81 percent of capacity, winding down in preparation for the shutdown required to refuel and install the new components.

Identical new equipment at Unit 3 will be installed this fall, Alexander said.

Earlier, the plant Dietrich said the newest of those generators had been running more than 600 days without incident, other than when it shut down for a couple days in response to the massive September power outage throughout Southern California.

Common Sense January 05, 2012 at 06:41 PM
Good job on the "multiple of three." Here in the U.S. our grid system operates at a frequency 60 hertz or 60 cycles per second. What that means is the flow of electrons in the wires changes direction - forward and backward - 60 times each second... i.e.., "alternating current." Europe and half of Japan operate at 50 cycles per second. So... in our country we design the generators to create alternating current at 60 hertz. The turbines that turn the generator will operate at a speed to generate the 60 hertz power given the design of the generator. For SONGS and most US power plants that speed is 1800 rpm. Some fossil plants are so-called "super-critical" plants that create steam at very very high pressures and their turbines spin at 3600 rpm - but then the generators are designed for that speed and still create electricity at 60 hertz. In both cases you are correct... the numbers are multiples of three.
Adam Townsend January 05, 2012 at 07:04 PM
An interesting side note that I deemed too technical to include in the main article is the number and size of the stages, or fans, in the turbine. As explained by Fred Simma, SONGS project manager and lead engineer for the turbine installation: In order to capture the most mechanical energy from the steam pressure, the smaller, high-pressure stages are in the middle, right where the steam enters the turbine housing. Here, the steam jets onto the blades with the most force. As it expands and dissipates, it needs to hit more surface area to exert enough force to turn the blades, hence the increasingly larger stages on either side of the turbine and its hour-glass shape (see the photo). A further efficiency improvement: Computer 3-D modeling determined that curved fan blades actually capture more energy from the steam than the older straight varieties--there are 1,600 of these blades in the new turbine.
george gregory January 05, 2012 at 08:46 PM
what material is the turbine made of,, monel,,,stainless steel ??/ the size of the output shafts are impressive also and look bigger than any I've seen is there any gearing or transmission before the gens. off the turbines ? the generators must be Hugh and impressive also are they open wound or incased for safety the info of Japan running two different hertz is laughable but does make a little sense considering their exposure to both Europe and the USA have a nice sunny so-cal day and stay safe
Common Sense January 06, 2012 at 02:14 AM
George Good questions all. The turbine you see in these pics is the High Pressure Turbine. There are actually three more even larger turbines behind it. All four turbines and their turbine shafts are connected and become one long train of spinning high grade steel. The High Pressure Turbine is closest to the generator - and there is no gearing. So the entire turbine generator set...about 1 million pounds...is rotating together at 1800 rpm. The turbines and generator are covered by very thick steel shells. There are cases where turbine blades have fatigues, broken, and spun off and penetrating the shell. Not a good day at the power plant. I was at a plant where we threw five blades. It was like losing the weights on your tire...but exaggerated a million times. Did a lot of damage. Realize...this part of the plant has nothing to do with the nuclear part. Turbines like these...but smaller..are common at coal fire plants around the world. Regarding Japan... the English and Americans were power players in the transformation of Japan to a modern country in the late 1800s/early 1900s. Tokyo and south went with US technology and the northern part adopted England's brand of generating equipment and transmissions systems. It is crazy...
george gregory January 06, 2012 at 08:10 PM
thank you for your time and the great answers I hope you change your name to professor instead of common sense can you imagine working or living in Japan cant move innless you buy a new refrigerator vacuum and blender or work innless you have two sets of power tools look who's talking in the land of SAE and metrics go figure


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