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First New US Nuclear Reactor In Two Decades Gets Permission To Begin Fueling (ieee.org)
An anonymous reader writes: The Tennessee Valley Authority's Watts Bar nuclear power plant began construction in 1973. The plant's first reactor was completed in 1996, and it began operation. Work on the second reactor paused in 1988, and only resumed in 2007. That reactor is now complete — the first newly-operational Generation II reactor since the 1990s. The new reactor has been granted an operational license, and it will soon begin fueling. While the Gen II reactors aren't unsafe, they're much less safe than the Gen III AP1000s. "Compared to a Westinghouse Gen II PWR, the AP1000 contains 50 percent fewer safety-related valves, 35 percent fewer pumps, 80 percent less safety-related piping, 85 percent less control cabling, and 45 percent less seismic building volume. ... If an accident happens, the AP1000 will shut itself down without needing any human intervention (or even electrical power) within the first 72 hours."
Have you ever visited a construction site after construction was stopped for any significant amount of time?
I've been to a couple of commercial construction sites (ie, mostly steel and concrete, versus wood for residential) where construction had stalled for a couple of years after the property value collapse, and crews were literally having to break-up concrete because unfinished exposed rebar ends had rusted and that rust expanded the rebar down into the concrete, causing cracks to begin in that concrete.
That was after only a couple of years. Imagine how bad it would get after close to 30 years. Buildings already have enough problems when they're finished if they don't get regular maintenance over the course of decades, but unfinished buildings that are not environmentally sealed will undoubtedly fare far, far worse.
I know that nuclear reactors are supposed to be structurally overengineered simply due to the nature the forces they contain, but starting out with a handicap due to building structural problems doesn't sound like the greatest plan, and that's before account for all of the other technical changes that have been engineered through the decades. We've already seen problems in younger reactors that were finished approximately on their original timetables, this seems like it's asking for more.
Do not look into laser with remaining eye.
My car has two doors, does that make it less safe then a car with 4 doors?
Well yeah, if you had to go through all of them to get out...
“He’s not deformed, he’s just drunk!”
The AP1000 has 72 hours of decay heat removal capability in the event of total loss of onsite power. If no action is taken to replenish cooling water, then decay heat would cause overheating and overpressure of the containment building and require venting of the containment building to the atmosphere. Radioactivity release from such venting is likely to be low unless meltdown or fuel damage has already occurred. Due to the large inventory of water within the containment building, decay heat is unlikely to result in meltdown for many days following the exhaustion of the containment cooling water.
In order to ensure integrity of the containment, additional cold water would need to be pumped into the containment building roof tank within 72 hours. This could be by restoration of the electrical supply, use of diesel powered water pumps held on site, use of portable water pumps held near site, or by use of fire pumps.
The ESBWR which is the main competitor to the AP1000, meets the Gen3+ requirement of 72 hours of decay heat removal without operator intervention. Like the AP1000, no diesel or grid power is necessary to meet this requirement. Like the AP1000, the ESBWR has 2(N+1) redundant UPS systems with 72 hours of battery autonomy for shutdown control and monitoring equipment. However, the ESBWR has a 7 day reserve of cold water for containment cooling. In the event of operator inaction, the UPS batteries will deplete after approximately 72 hours, but passive containment cooling will continue for up to 7 days before water tanks would need to be replenished.
I am. I have a job as an engineer in the military industrial complex. I've also been told to drop what I'm doing because of $BULLSHIT_ADMINISTRATIVE_REASON only to have to pick it up again a year or more later and waste time getting myself and the right people back on track. I've also seen my colleagues do the same, and I've seen all of get screwed by the fact that after $WAITING_PERIOD, the resources we had marshalled the first time around aren't quite so easy to marshal the second time around, especially when you pull the rug out from under people enough times, they don't want to work for/with you the next time when for real, I swear, we have the funding to finish it, promise. If it's true for the 10M programs I've worked on, it's true times a hundred for a billion-dollar power plant.
Here are full details, with appropriate references, about the idea ending the reliance on fossil fuels in the US requires nuclear to be a significant part of the energy mix:
https://docs.google.com/docume...
The summary is that solar, wind, hydro, and geothermal can make an important contribution, providing a significant portion of our energy needs. A very significant portion cannot be solved by those four choices - for reliable, steady power in huge amounts the choices are fossil fuels or nuclear.
As I understand it the US has about 18GW of solar PV installed capacity with about a 28% capacity factor - so roughly 5 GW of actual power generation.
These two reactors together will generate about 2.2GW with a 90% factor, or around 2 GW.
One power plant, 40% of the capacity of all PV in the country.
A couple of comments. I worked at Watts Bar for 6 years - from just before they restarted construction until 2013. I now work out at one of the new reactors under construction at VC Summer.
First off, WBN2 and WBN1 share structures. Actually, all the structures except for the reactor building itself is shared. The units are what is considered an "opposite hand" configuration, which means that essentially a piece of equipment, piping, or valve on the far west side of the plant for U1 would be on the far east side, at the same northing, for U2 with everything matching up in the middle. The units also share many systems, and in order for them to start up U1, they had to have those systems (and many of the U2 pumps, valves and other support equipment) in service. The units also share a control room, spent fuel pool, diesel generators, and more. The only completely independent structure is the reactor building, which was structurally complete when they halted construction. Most everything inside was complete (major equipment set, piped in, etc). Most of what was lacking were control systems, instrumentation, and some valves. Also, all of this equipment was under temperature and humidity controls during the layup period.
One other thing - all of these structures are reinforced concrete. The unique thing about concrete is they get stronger with age unless you have something like saltwater causing problems. They're also *very thick* and *heavily reinforced* concrete - as in, the age isn't a handicap at all.
I hate sigs...