Watts Bar Unit 2: Impact on Industry?

[Cumberland]

With Watts Bar Unit 2 expected to begin operating this month, will it have any significant effect on the industry? It's somewhat a milestone.

 

[russ_watters]

Awesome!

[googles]

Well...kind of awesome:

Unit 2 was 80% complete when construction on both units was stopped in 1988 due in part to a projected decrease in power demand.[1] In 2007, the TVA Board approved completion of Unit 2 on August 1, and construction resumed on October 15.[2]

https://en.wikipedia.org/wiki/Watts_Bar_Nuclear_Generating_Station

While it's nice to see and we'll see what kind of press it gets, it isn't quite the unequivocal sign of the resurgence of nuclear power that I need to see to believe it is really on the way back. Because it was an existing plant and partly completed construction project, virtually all of the red-tape associated with constructing a nuclear plant that usually gets it blocked has already been overcome... ...environmentalists be like "hey, wait a minute, when did that happen? I didn't get a chance to sue anyone or nuthin!"

 

[Astronuc]

Well, it will be generating revenue and return on investment, and that's a good thing. TVA couldn't embark on other projects until this one got going.

 

[mheslep]

Awesome!

[googles]

Well...kind of awesome:

https://en.wikipedia.org/wiki/Watts_Bar_Nuclear_Generating_Station

While it's nice to see and we'll see what kind of press it gets, it isn't quite the unequivocal sign of the resurgence of nuclear power that I need to see to believe it is really on the way back. Because it was an existing plant and partly completed construction project, virtually all of the red-tape associated with constructing a nuclear plant that usually gets it blocked has already been overcome... ...environmentalists be like "hey, wait a minute, when did that happen? I didn't get a chance to sue anyone or nuthin!"

There are four other brand new reactors currently under construction in the US with NRC approval. Two in GA at Vogtle, two in SC at Virgil. The 1st Vogtle reactor is scheduled to start around 2019. The five together, including Watts Bar, will produce about 6 GW. The small modular reactor (SMR) company Nuscale has agreements in place with Utah utilites to build reactors, and the NRC has made highly encouraging statements about their design. About 10 years out.

 

[Pengtaofu]

Watts bar-2 has came into commercial operation in October 2016. By the way, the PWR model of Watts bar-2 is W(4-loop) (ICECND) according to IAEA-PRIS website(https://www.iaea.org/PRIS/CountryStatistics/ReactorDetails.aspx?current=699). I know the W(4-loop) means PWR with 4 loops, however what does (ICECND) mean? Is Watts bar-2 AP1000 unit?

 

[silverback011]

I believe ICECND is short for isolation condensor.

https://en.wikipedia.org/wiki/Isolation_Condensor

 

[Hiddencamper]

I believe ICECND is short for isolation condensor.

https://en.wikipedia.org/wiki/Isolation_Condensor

No it's an ICE condenser.

Watts bar uses ice vaults which act as a steam suppression system. If a leak occurs or there is a primary system leak into the containment, the steam enter the ice vault and is essentially quenched by the ice, limiting peak containment temperature and pressure similar to a suppression pool in a BWR.

In fact, the ice condenser PWR containment is much smaller in size compared to a dry PWR containment. The ice condenser containment is about the same size as the mark 3 BWR containment which uses a suppression pool.

There are a handful of ice condenser plants such as DC cook. These mid sized containments (ice condenser PWR and mark 3 BWR) have hydrogen combustion concerns during post accident conditions which require hydrogen control systems. Large PWR containments don't have a concern due to their size, and small BWR containments are inerted with no oxygen so they also don't have hydrogen combustion concerns.

 

[Astronuc]

Watts bar-2 has came into commercial operation in October 2016. By the way, the PWR model of Watts bar-2 is W(4-loop) (ICECND) according to IAEA-PRIS website(https://www.iaea.org/PRIS/CountryStatistics/ReactorDetails.aspx?current=699). I know the W(4-loop) means PWR with 4 loops, however what does (ICECND) mean? Is Watts bar-2 AP1000 unit?

With respect to Watts Bar units 1 & 2, they have ice condensers in their containment.

Containment Type: Wet, Ice condenser
http://www.nrc.gov/info-finder/reactors/wb2.html

The ice condenser is a safety system designed to rapidly condense steam and reduce containment pressure following a LOCA or a main steamline break (MSLB).

Watts Bar is not an AP1000, but rather an older standard 3411 MWt, 4-loop (193 assemblies in the core) 17x17 PWR design. Watts Bar was contemporary with D.C.Cook 2, Sequoyah 1&2, McGuire 1&2 and Catawba 1&2, which have wet containment with ice condensers, and Diablo Canyon 1&2 and Salem 1&2, which do not, i.e., this latter pair of plants have dry containment.

Some good information on containment evolution here - https://www.fas.org/sgp/crs/misc/R41805.pdf

 

[silverback011]

Thank you for clearing that up and providing detailed responses. I learned some new things.