Thank you very much for your comments. I believe some of us have corresponded on linked-in, but in case anyone has not seen my responses, I will also post them here.

Mr. Knuckles, than you very much for your insights on the refueling debates. Your thoughts are very similar to mine and I greatly appreciate your expanded technical explanation.

S.J.- I completely agree that SMRs could and should be part of the solution but cannot be exclusively relied upon.

Mr. Bell,

In this article I was talking about retail cost estimates for individual modules, thus not factoring in engineering and licensing etc. The economics of learning are certainly important. One of the problems with these figures is that they are only estimates and many of the most accurate figures aren’t publicly available.

Shortly after publishing this, I received an email about GE Hitachi’s PRISM Reactor pricing that was outside of the numbers I quoted. Unfortunately it was too late to make an adjustment. If you have anything you think I should read, I would greatly appreciate your sending it along. There’s lots of information out there and it’s difficult to keep up!

However, I would like to note that I have seen sale price estimates for Hyperion’s first design around $25 million per module. The new design has I believe been upped to $50 million per module.. So there are some ‘inexpensive’ designs out there…

You could very well be right about the size of guard forces. My thought is just that a balance needs to be found between use of security personnel and inherent safety mechanisms, and that design improvements should not be relied upon too heavily before they have been proven in operation, especially for plants in high risk areas.

I have a couple observations that might help your research.

- $25-500 million a copy is too low of a cost for a nuclear power plant. $2 billion a copy and ~$5 billion for the first units (including non-recurring engineering, qualification testing, tooling, etc.) is more realistic and more consistent with numbers I have heard used by serious reactor vendors exploring SMRs.

- The key disadvantage of many SMR concepts is putting safety-critical equipment (control drives and pumps) in a harsh, primary water environment where it will inevitably fail. The equipment is not necessarily fail-safe, meaning that certain kinds of control drive mechanisms can fail in this environment in such a way that the control rod will not insert. Failures during operation will cause disruptive and costly down time. Equipment replacement is costly and difficult, as is connecting and disconnecting electrical equipment in a radiation field during refueling. The costs and risks associated with emergent equipment failures should be weighed in the SMR business case. I expect that compared to known technologies, like making piping welds, the cost and risk of putting equipment inside the reactor vessel for a perceived “factor construction benefit” is not worthwhile.

- While I am not an expert, I do not think that the size of the installation controls guard force size or security costs. My understanding is that security requirements are designed around a threat to be guarded against and not strongly dependent on site size for something the size of even a small nuclear power plant. You might want to research the requirements more.

Otherwise, thanks for your article.

I believe standardization of equipment and design of new and/or revamped generating stations would also have cost cutting benefits for construction and operation. One of the benefits of standardization is the reduction of maintenance and re-fueling costs due to having a cadre of maintenance/re-fueling workers that travel from one plant to the next.

As it is today each plant relies heavily on contract workers in every discipline to assist in re-fueling and/or maintenance evolutions. Having been an Outage Coordinator in the containment structure at Diablo Canyon during re-fueling activities it was apparent that those outage workers not familiar with the plant layout, equipment, tooling and policies were less efficient than those that were more familiar.

There is also the NIMBY problem of the positioning of new plants mainly associated with the issue around the storage and/or disposal of spent fuels. It’s been my experience that most communities don’t want a nuclear plant in the neighborhood. I believe that positive education of the public, not just an Ad campaign is necessary to overcome the stigma associated with nuclear power stations. The risks as well as the benefits must be addressed openly. Community by-in is absolutely vital to the future of the industry, and SMR’s just might be a key to public acceptance of this much needed piece of our energy picture.

As someone with seventeen years experience in nuclear power generation I want very much to see this industry flourish. I’m all for anything that would allow our industry to move forward.

Off-site refueling of the SMR has a distinct disadvantage should one of the fuel assemblies fail; it forecloses the possibility of “repair” on-site which in itself is a complicated but doable process. It is reasonable to expect such failures to occur in a new fuel design such as those proposed for the SMR. Such failures in large scale LWR fuel assemblies have occurred and are related to either manufacturing or operation but have occurred on a decreasing frequency as their fuel designs have matured. These types of failures usually entail small breaches of the metallic cladding surrounding the fissionable material and the subsequent release of radioactive fission products into the surrounding coolant. The return of a sealed vessel containing damaged fuel to the manufacturer can be expected to be a more costly and environmentally risky affair than on-site repair because the fission products are less securely contained during transport than if the fuel had not been damaged.

Best,

Edward

Apologies for the late response. I just saw your comment. 2 of the most prominent models, NuScale and Babcock and Wilcox’s mPower are designed to use standard LWR technology. A third design, the Hyperion Power Module is designed for lead-bismuth coolant. Please see pages 15 and 35 of the following study for a complete list of advanced SMR designs along with currently deployable models, respectively. Paste the link into google or it won’t work. Charts on these pages describe the fuel specifications of the various reactor designs. Please remember that not all SMRs are modular. The acronym can mean either ‘Small Modular Reactor’ or ‘Small/Medium Reactor’ (defined by the IAEA as a capacity of 300-700MWe per individual module).

http://home.nea.fr/ndd/reports/2011/current-status-small-reactors.pdf

Let me know if you have any more questions.

Best regards,

Edward

Thanks for the interesting article. I confess that I dont know much about SMRs – what type of fuel do they use ? Is it similar to LWRs or would major investment in fuel fabrication facilities be required ?

Thanks

Richard

Thank you very much for your comments. It is wonderful to dialogue with people who are informed about energy issues.

Karen,

I completely agree with you. Your concerns about off-site refueling figured heavily in my masters thesis and are an important theme in an article I am writing about SMRs’ potential in developing countries. I have had an ongoing conversation with several prominent potential SMR manufacturers. I can tell you that:

NuScale originally planned to use off-site refueling, but abandoned this prospect after rethinking the economics and logistics. However, some companies still favor off-site refueling. They have justified it to me as a matter of operators’ personal choice. In their view, some utilities may have no problem opening the reactor core to engage in on-site refueling, while others might view their circumstances as better suited for permanently-sealed reactor designs requiring off-site refueling.

In my opinion, off-site refueling’s detrimental risks which you mentioned, make it an issue too substantial to be dictated by preference. Furthermore, the belief espoused by potential SMR manufacturers that accidents would not merit off-site evacuations, would be an additional strike against off-site refueling if proved correct.

If you haven’t already seen it, you might find this link interesting http://appropriations.senate.gov/ht-energy.cfm?method=hearings.view&id=debb45d6-adb1-41f0-a608-cc7a4965f934

It has all of the written testimony of parties involved in the July 2011 US Senate Appropriations Committee hearing on SMRs. A link to a video of the hearing is there as well.

Pietro,

Passive cooling systems were explained in paragraph thirteen. I apologize for not going into greater depth. However, I was trying to write concisely. Regarding your other points, I would like to recommend that you read the following NEA study (paste the link into google or else it won’t work) http://home.nea.fr/ndd/reports/2011/current-status-small-reactors.pdf

Sections 8.5-8.7 on pages 124-127 discuss the potential specifications of various SMR designs with alternate coolants

George,

I was thinking in terms of overall volume of waste. For example, compared to a gigawatt scale reactor, a full-capacity 640MWe mpower plant or a 540 MWe NuScale plant would produce less. However, if SMR capacity outweighed gigawatt-scale capacity in a given geographic area, this would not be the case.
You might find interest in page fifteen of the study I cited in my response to Pietro. It projects that due to their smaller reactor core, SMRs would generally not be as neutron-efficient as large reactors.