There's no imminent problem at San Onofre. In fact, both reactors are shutdown pending the resolution of this problem.
What they have really isn't a problem in the sense that it could lead to a safety issue.
Basically, what they have is a "wear" problem. The tubes in the steam generator are experiencing faster "wear" than they should.
It's as if your new shoes are wearing down faster than you expect. You expect to get a year or more worth of wear from your shoes; and your new shoes look like year old shoes after just a few months. Is that a major safety issue for you? Are you in danger of walking with your feet unprotected??
NO - it means that if they did nothing, they would have to replace their new expensive steam generators in a couple years, instead of getting a couple decades worth of wear out of them.
But it doesn't mean that there is going to be a safety problem from a wear issue.
Are you afraid of landing in an airliner because you fear the tires are all going to blow out due to wear on landing. Even if the airline got some tires that were wearing out faster than expected; they still monitor the tread on those tires and will replace them earlier so their planes remain safe.
It is more of a cost issue than a safety issue. SCE was so cheap that it only purchased only one set of steam generator nozzle dams that are necessarily for testing the tubes in question, so it is technically impossible to test the steam generators in both units 2 and 3 at the same time. This is the reason that the testing is taking twice as long. Before Nuclear Regulatory Commission Chairman Gregory Jaczko visited the plant, it was the intention of SCE just to pressure it up and see what happened. "They have to demonstrate to us that they understand the causes and that they have a plan to address the causes that assure public health and safety," Jazcko said after his visit. As a result of this SCE is loosing $600,000 a day and looking at restarting retired gas turbines to meet summer demand. The safety problems that caused the leak could well be related to the fact that the generator replacements were not apples for apples. The alloys are different, the flow rate is different, the number of tubes are different and the supports for the tubes inside the generator are different. The NRC has said that the excessive wear of the tubes appeared to be caused by vibrating and rubbing against nearby tubes and against support structures inside the steam generators. Jaczko said that while degradation was found in some steam tubes in Unit 2, it was a "different type of degradation" from the type found in Unit 3, which was more excessive. "It is possible they could move forward on a different path for restart [of Unit 2] but they'll have to address that as part of their analysis," Jaczko said.
"Officials said the investigation has yielded a better understanding about why the tubes are wearing down. When the plant is running at full power, the rate of steam flow is causing the tubes to vibrate, much like a guitar string being plucked. Some tubes vibrated enough that they rubbed against each other, causing the tube walls to wear down much faster than expected.
This is a potential danger because tube ruptures could release radiation and in extreme cases compromise the reactors' cooling system."
Several experts said the problems suggest a design flaw.
"This is very unusual behavior in steam generators, and I think the most likely scenario was that there was some error in the design," said Per Peterson, chairman of the University of California, Berkeley's Department of Nuclear Engineering.
Peterson suspects the problem involves the design of support structures meant to prevent excessive vibration. He added that the solution suggested by Edison - running the plant at a lower power level - would probably address the vibration problem but would result in less power, cutting into Edison's revenues.
OH BROTHER!!!
There's no imminent problem at San Onofre. In fact, both reactors are shutdown pending the resolution of this problem.
What they have really isn't a problem in the sense that it could lead to a safety issue.
Basically, what they have is a "wear" problem. The tubes in the steam generator are experiencing faster "wear" than they should.
It's as if your new shoes are wearing down faster than you expect. You expect to get a year or more worth of wear from your shoes; and your new shoes look like year old shoes after just a few months. Is that a major safety issue for you? Are you in danger of walking with your feet unprotected??
NO - it means that if they did nothing, they would have to replace their new expensive steam generators in a couple years, instead of getting a couple decades worth of wear out of them.
But it doesn't mean that there is going to be a safety problem from a wear issue.
Are you afraid of landing in an airliner because you fear the tires are all going to blow out due to wear on landing. Even if the airline got some tires that were wearing out faster than expected; they still monitor the tread on those tires and will replace them earlier so their planes remain safe.
It's more of a cost issue than a safety issue.
It is more of a cost issue
It is more of a cost issue than a safety issue. SCE was so cheap that it only purchased only one set of steam generator nozzle dams that are necessarily for testing the tubes in question, so it is technically impossible to test the steam generators in both units 2 and 3 at the same time. This is the reason that the testing is taking twice as long. Before Nuclear Regulatory Commission Chairman Gregory Jaczko visited the plant, it was the intention of SCE just to pressure it up and see what happened. "They have to demonstrate to us that they understand the causes and that they have a plan to address the causes that assure public health and safety," Jazcko said after his visit. As a result of this SCE is loosing $600,000 a day and looking at restarting retired gas turbines to meet summer demand. The safety problems that caused the leak could well be related to the fact that the generator replacements were not apples for apples. The alloys are different, the flow rate is different, the number of tubes are different and the supports for the tubes inside the generator are different. The NRC has said that the excessive wear of the tubes appeared to be caused by vibrating and rubbing against nearby tubes and against support structures inside the steam generators. Jaczko said that while degradation was found in some steam tubes in Unit 2, it was a "different type of degradation" from the type found in Unit 3, which was more excessive. "It is possible they could move forward on a different path for restart [of Unit 2] but they'll have to address that as part of their analysis," Jaczko said.
http://online.wsj.com/article/BT-CO-20120406-705355.html
= uprate couldn't be harder on tubes?
Well ,San onofre was uprated reactors 2 and 3 so the utility could make more electricity =,more strain on equipment perhaps that's my uneducated guess ...tdm
http://www.nrc.gov/reactors/operating/licensing/power-uprates/pwr-mur/sa...
http://www.bellinghamherald.c
http://www.bellinghamherald.com/2012/05/20/2529417/san-onofres-future-hi...
"Officials said the investigation has yielded a better understanding about why the tubes are wearing down. When the plant is running at full power, the rate of steam flow is causing the tubes to vibrate, much like a guitar string being plucked. Some tubes vibrated enough that they rubbed against each other, causing the tube walls to wear down much faster than expected.
This is a potential danger because tube ruptures could release radiation and in extreme cases compromise the reactors' cooling system."
Several experts said the problems suggest a design flaw.
"This is very unusual behavior in steam generators, and I think the most likely scenario was that there was some error in the design," said Per Peterson, chairman of the University of California, Berkeley's Department of Nuclear Engineering.
Peterson suspects the problem involves the design of support structures meant to prevent excessive vibration. He added that the solution suggested by Edison - running the plant at a lower power level - would probably address the vibration problem but would result in less power, cutting into Edison's revenues.
Read more here: http://www.bellinghamherald.com/2012/05/20/2529417/san-onofres-future-hi...
Read more here: http://www.bellinghamherald.com/2012/05/20/2529417/san-onofres-future-hi...
Um ... No?
Um ... No?