27. Musings on Unused CR3 Steam Generators

There was some somewhat bad news in the nuclear world this week. Duke Energy announced that the Crystal River Unit 3 (CR3) nuclear plant, that was obtained as part of the Duke-Progress merger, will be decommissioned rather than repaired after not operating since a 2009 outage.

During the 2009 outage, a hole had to cut in the containment to allow for new steam generators to be installed. As part of cutting the hole, the containment's concrete was cracked. An initial crack was repaired, but then in 2011, there was additional damage. This put Progress Energy, and following the merger Duke Energy, into the position of having a very tough decision to make of whether it would prove to be economical to repair the containment. It should be noted that the damage was not irreparable damage, but that the repairs carried enough uncertainty (both cost and schedule-wise) that the damage proved to be uneconomical to repair.

The 2009 outage included replacing CR3's steam generators. Replacing steam generators is far from a trivial maintenance operation, considering steam generators weigh in the hundreds of tons. Here is a rather incredible time-lapse video of the replacement of the 4 steam generators at Sequoyah Unit 2 which occurred towards the end of 2012.



Since Crystal River 3 never came back online following that outage, the steam generators have never entered service and should be brand new for all intents and purposes. With such valuable pieces of equipment being free of any wear and tear (other than being welded into place within the CR3 reactor coolant system, feedwater system, auxiliary feedwater system, steam generator blowdown, and main steam systems), it would be nice if they could somehow be re-used somewhere for their designed purpose of generating steam (with zero emissions, of course).

Being the entrepreneurial thinker that I am, I spent a few minutes trying to think of a few options to re-use these very valuable components. Here are the 3 options, in the order in which they came to mind.

1. San Onofre Nuclear Generating Station (aka SONGS) Units 2 and/or 3

This would almost be a perfect match, considering the SONGS early-life steam generator wear issue that has kept both Units 2 and 3 there shut down since January 2012. Sadly though, there are several extremely intractable problems that would arise from trying to fit the CR3 steam generators into either unit at SONGS that would make such an arrangement an impossibility economically. CR3, being a B&W-designed plant, has a completely different steam generator design than the Combustion Engineering-designed plants at San Onofre. The engineering and modifications that would be necessary to put once-through B&W steam generators (OTSGs) into a Combustion Engineering plant with U-tube steam generators would be intractable, sadly. It would be pretty far beyond trying to fit a square peg into a round hole. The biggest reason for this being that OTSGs have the primary side water enter at the top of the steam generator, whereas U-tube steam generators have the primary side enter at the bottom.

Additionally, Crystal River’s lower designed core thermal power (2609 MWt) would be poorly matched to the designed core thermal power of either of the San Onofre units (3438 MWt). The power level would be rather close to the 70% level that has been proposed by the owners of San Onofre Unit 2 for the trial 5-month period after restart.

2. TVA's Bellefonte Unit 1, scheduled to come online around 2021-ish

TVA had maintained the partially/mostly-completed plants at Bellefonte for quite a few years prior to cutting into their steam generators and selling the metal from the steam generator tubes in the 2006 or 2007 time-frame. With no tubes, a steam generator is basically worthless for its intended purpose. So, as one of the earliest steps following the August 2011 decision to complete construction of Unit 1 at Bellefonte, the procurement process for new steam generators was at least kick-started. I have no knowledge of how far along that process is, but I do know that Bellefonte, like CR3, is a B&W-designed plant. The 2 plants at least share the once-through steam generator (OTSG) aspect of their design. Sadly, the power level of Bellefonte is grossly mismatched from what the CR3 SGs were designed for (3,600 MWt vs. 2609 MWt , >1200 MWe vs. < 900 MWe, and 205 fuel assemblies vs. 177 fuel assemblies).

3. One of the 3 Duke-owned Units at Oconee  

Ah, finally, this could be a great place to utilize this pair of enormous and valuable components - three units to pick from, B&W-designed, entered initial operation at almost the same time as Crystal River Unit 3, now owned by the same parent utility as CR3 following the Duke-Progress merger, and nearly exactly the same power level as CR3 (2,568 MWt vs. CR3's 2,609 MWt). But alas, the 3 units have had their SGs replaced since 2003, so with a good chemistry program in place to prevent corrosion, etc. the units at Oconee could very well not need new steam generators during the duration of the 20-year license extensions they have already received. Maybe they will need them during a subsequent 20-year renewal period.

Concluding

So, maybe there is no good way to actually utilize the Crystal River Unit 3 steam generators at this time. The amount of work that would be required to remove them from CR3 and transport them to anywhere other than where they are positioned right now within the CR3 containment building would be considerably expensive, so the best place for them at this time is likely right where they are. Also, as the NEI blog, Nuclear Notes, noted in a posting on the same subject, who knows what the future might hold. Perhaps Rod Adams will prove prophetic in his bet with Steve Skutnik regarding natural gas prices and repairing Crystal River could make economical sense.