Friday, May 11, 2012

Supercritical CO2 turbine being developed for SMRs

A former scientist at Sandia National Lab is bringing the technology to market

Temperature / Pressure
ranges for supercritical CO2
Image: S. Wright
Carbon Dioxide is good for a lot of things like adding fizz to your soft drinking in its gaseous form and keeping food cold in its solid form as “dry ice.”

What many people do not know is that the gas is also useful in its lesser known liquid form. You won’t see it in nature since it takes five atmospheres of pressure at slightly higher than room temperature, 31C, to take it to a super state.

Then it can be used to push turbine blades and thus generators connected to them to make power. (Note to readers: Convert Kelvin to Centigrade using this tool.)

Because of its physical properties as a liquid, it has become a target fluid of opportunity to run turbines and thus make electricity. Steven Wright, Ph.D., who recently retired from Sandia National Laboratory (SNL), has set up a consulting company called Critical Energy LLC to bring this technology to a commercial level.

The objective of using supercritical CO2 (S-CO2) in a Brayton-Cycle turbine is to make it much more efficient in the transfer of heat. Wright points out that a steam turbine is about 33% efficient, but that an S-CO2 turbine could be as high as 48% efficient, a significant increase.

A closed loop supercritical CO2 system has the density of a liquid, but many of the properties of a gas. A turbine running on it, “is basically a jet engine running on a hot liquid,” says Wright.

“There is a tremendous amount of scientific and industrial interest in S-CO2 for power generation. All heat sources are involved including solar, geothermal, fossil fuel, biomnass, and nuclear.”

Barber-Nichols S-CO2 turbine wheel
Photo: Sandia National Laboratory
Size matters

It is that last area that has Wright focused on small modular reactors or SMRs. Because developers of reactors in the range of 45-200 MW have promised customers that these compact power units can be delivered to a site on a truck, or by rail, they need turbines of similar scale.

A set of S-CO2 turbines and compressors is is about 3-4% the size of a conventional steam generator of similar power rating. The heat exchangers, taken together with all other components, brings in a configuration that is 30-40% smaller than for similar steam systems.

The footprint of a S-CO2 turbine, compressor and heat exchangers for a 50 MW system would be scaled accordingly, but would still have a smaller footprint than a comparable steam system.  It would be more than a couple of shipping containers, but less than a whole barge of them.

In January 2012 Wright wrote about his work and the fabrication of prototype parts by the firm of Barber-Nichols in Arvada, Colo.

Q&A with the principal investigator

This blog talked with Wright by phone this week. Here’s what he had to say.

Q: The paper mentions a reactor outlet temperature of 500-700C. Is there an ideal temperature coming off the reactor? Also, what is the temperature of the return loop?

A: For a fast reactor with an outlet temperature of 550C, the return loop is 500C. The very small temperature differential means you don’t have to push a lot of heat getting the return loop back up to the right temperature again. The temperature differentials for the CO2 in the secondary loop would be about 150C.

“The small temperature differential makes it more efficient”

Wright claims that as a practical matter, at any reactor outlet temperature above 400-450C, CO2 exceed steam for efficiency.

“These temperatures are consistent with sodium-cooled or other liquid metal cooled and gas cooled fast reactors. The temperatures are not so high that you get into materials issues for containing the heat. The upper boundary is about 650C.”

Conceptual drawing of sodium-cooled
fast reactor: Image: Idaho National Laboratory
In terms of achieving commercial success, Wright is focused on temperatures starting at 500C because he knows he can get stainless steel fabricated from commercial sources that will operated in his design.

Also, he has found through his work that he can get commercial bearings and seals to work well in this temperature range.

Q: Your prototype at Sandia ran at very high speeds. How do you plan to get the power transferred from the turbine to a generator?

A: We are planning for a turbine speed of 36,000 RPM which can be stepped down in a 10:1 gearbox to 3600 RPM to produce power at 60 Hz.

Q: Recognizing that a S-CO2 turbine is not a combustion unit, like one in a jet engine, what are the key technical challenges to scaling up to commercial size?

A: The key challenge will be to build a 100-200 MW unit to show that everything works. My focus is to get the cost and design of the heat recuperators to meet commercial needs. They must be small, compact, and affordable.

Our plan for a 10 MW prototype has two of them using very small channels. In our lab prototype, we have two of them that are operating which were fabricated for us by Heatric.

Recuperator conceptual diagram
Image: Science Direct
The recuperators are used to increase the overall efficiency of the system. The recuperator transfers some of the waste heat in the return loop  preheating the CO2 before it contacts the primary loop again.

Since the CO2 is pre-heated, less energy is needed to then heat it up to the turbine inlet temperature. By recovering some of the energy usually lost as waste heat, the recuperator can make a supercritical gas turbine significantly more efficient.

The recuperators on the S-CO2 systems work much the same way as a gas fired turbine except they are heating a noncombustible gas instead of air to be mixed with fuel.

Q: You indicated that a first-of-a-kind system producing a 10 MW system could be $20-30 million. Do you have a cost estimate for an “Nth of a kind at 50 MW?”

A: Our target is a cost of $1 a watt. If we can find the right industrial partners, we could produce the first units for non-nuclear power applications in three-to-five years.

Separately, Wright said that to use the turbines with small modular reactors (SMRs), they would have to be evaluated as safety-related equipment by the NRC or any nuclear safety agency elsewhere.

He wants to see a revenue stream from non-nuclear applications before spending money on the cost of a regulatory process that covers equipment for nuclear power stations.

Asked about licensing and partnering opportunities, Wright refers inquiries to the Technology Transfer Office at Sandia.  See also this Sandia press release.  For additional technical information, go to the S-CO2 Power Cycle web site.

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Thursday, May 10, 2012

Watts Bar: Fairytale or True to Life Story

The project will come in three years late and $2.5 billion over budget

This is my updated coverage from Fuel Cycle Week V11:N471 May 3, 2012, published by International Nuclear Associates, Washington, DC

Once upon a time an ailing king abandoned one of his castles. He said it was too expensive to keep up more than one court. Besides, the peasants weren’t bringing in the sheaves, which made the whole kingdom’s economics shaky.

Then a new king arose, who was wiser in the ways of castle upkeep.

“We can reopen the closed court,” he boasted, “and for half the price of building a new one!”

Excited about restoring the realm to its former glory, the builders set out to their task. Like ants they swarmed over the ramparts, each to his or her appointed place. But as they worked, the new king noticed something was wrong.

“There are too many workers,” he thought. “I’m paying a fortune for their labor, but they’re getting in each other’s way!” So the king went back to his court, and asked his treasurer and his wise men, “what should I do?”

“Fire a bunch of workers and let the work go slower,” they said in unison. No one would mind if the castle was three years later than expected.

“But the cost of building goes higher every year,” the king complained.

“Don’t worry!” cried his advisers. “The castle will last at least 60 years, and your grandchildren might get another 20 years. You’ll get your value out of it because you and your family will use it a long time.”

Fairytales vs. True Confessions

This fairy tale is brought to you by the Tennessee Valley Authority, which in 2007 restarted construction of the mothballed 1200 MWe Watts Bar 2 nuclear reactor. The workers swarmed over the 55%-completed reactor just like the fairytale workers. The employer, Bechtel, promised to complete the reactor for about $2.5 billion by 2012.

But soon there were problems due to safety lapses, quality assurance issues and a slower pace of completing work than the aggressive schedule allowed. In August 2011 TVA CEO Tom Kilgore took the reins back from Bechtel and ordered a new cost and schedule baseline.

This week the TVA Board of Directors accepted a new cost estimate that adds $1.5-2 billion to the bottom line and brings the reactor online three years later, sometime in the fourth quarter of 2015. The total cost estimate could be as high as $4.5 billion and full time to completion is now eight years. The target cost is $4.2 billion.

A Bargain at Twice the Price

Kilgore believes that completing the reactor is still a bargain compared to putting up a new one at today’s overnight price of about $5,000/kw. That would make a 1200-MWe reactor come in at $6 billion or $1.5 billion more. That’s the equivalent of 1500 $1-million lottery tickets and Kilgore is betting that every one of them will pay off.

There are good reasons for this optimism. According to TVA, the impetus for wanting to complete the project starts with having a reactor pressure vessel in place. As of February 2012, the project has moved from being 55% complete in 2007 to 80% complete, and with pluses and minuses for progress on electrical and mechanical work.

Tough Case to Keep Going

Kilgore still had a tough case to make with the TVA Board to keep the work going on the reactor a second time. None other than former TVA Chairman S. David Freeman said the new cost overruns showed it was time to put the brakes on the project. Freeman said the new story is the same bad story that persuaded him to pull the plug on runaway costs at reactor projects in the 1980s. TVA could get better results for its money by investing in energy efficiency, demand-response management and renewable energy.

One cause of cost overruns in the 1980s was that EPC firms did the engineering work based on designs as they were building the project. At last week’s TVA board meeting, Mike Scaggs, the TVA manager in charge of construction at Watts Bar 2, said that, in retrospect, more design work on the semi-complete reactor should have been done up front, rather than while the plant was already under construction.

Overall, Kilgore and Scaggs told the board that the cost increases were the result of poor estimates and they said the reviews of those estimates were incomplete. They pledged that the new estimates were much better.

In spite of all these daunting problems, stopping work on Watts Bar 2 was never an option for the TVA board. In a company statement TVA Board Chairman Bill Sansom said the board “endorsed the leadership and actions of…Kilgore and his team.”

TVA also plans to restart work on the Bellefonte 1 reactor, as soon as they load the fuel into Watts Bar 2. The three-year delay to finish the first reactor most likely pushes completion of Bellefonte 1 past 2020. Last month TVA laid off half the workforce at Bellefonte as the utility changed is schedule for Watts Bar 2.

TVA Financials in a Nutshell

The utility said in a filing with the SEC it suffered a net loss for the second quarter and a projected loss for the budget year, TVA officials said it would cut 1,000 jobs and delay capital projects including work to complete Bellefonte Nuclear Power Plant. That action is expected to save $150 million.

The federal utility reported a net loss for the first half of fiscal 2013 of $267 million on sales of less than $5.2 billion. In the same period in 2011, the Tennessee Valley Authority earned $205 million on sales of $5.8 billion.

TVA Financial Operating Manager John Thomas cited unusually warm weather and a sluggish economy on the downturn.  He said costs will increase due to increased spending to complete the the Watts Bar 2 nuclear reactor.

In March, TVA laid off 430 of the 900 contractors working on the Bellefonte project, the utility's partially complete nuclear plant.

The Watts Bar reactor already is overbudget and behind schedule, and officials say it will take three more years and up to $2 billion more than expected to finish.

TVA President and CEO Tom Kilgore said the increased costs for Watts Bar overruns will not raise rates.

Cameco Bullish On Japan Comeback

The country's nuclear utilities aren't selling off their uranium

This is my updated coverage from Fuel Cycle Week V11:N471 May 3, 2012, published by International Nuclear Associates, Washington, DC

Tim Gitzel, Cameco CEO
In the midst of reporting excellent financial results for 1Q2012 during a May 1 conference call for financial analysts Cameco CEO Tim Gitzel said he believed Japan would restart its nuclear reactors—and soon.

“The fleet will come back online,” he said, adding that the Japanese economy’s need for power drives its major nuclear utilities’ continued investment in joint development of uranium mines with Cameco.

Also, despite suggestions that Japanese utilities might step back from long-term contracts, Gitzel said there had been no major unloading of inventory from Japan, nor any offloading from their utilities into the spot market. Gitzel said he still worries about excess Japanese inventories, but so far hasn’t seen any movement of them into the market.

The rest of the global nuclear industry is watching what is happening in Japan because, unlike Germany, in which the political establishment has made a firm decision to phase out all 17 of its nuclear reactors, Japan’s current political leadership is committed to restarting a fleet that is three times that of the Germans.

Gitzel said that when Japan’s reactors come back online, it would be a confidence builder for the global industry. He pointed out that 96 new nuclear reactors will come online over the next decade and 63 are already under construction. He cited India and China in particular noting that he just came back from a trip to India where officials there told Cameco they would build 60 GWe of nuclear generating capacity in the next two decades.

Supply Issues Could Dog Industry

The expansion of nuclear reactors, which is also occurring in the U.S. and U.K., means the market will call for more supply. Gitzel said Cameco remains committed to it goal of producing 40 million pounds of uranium by 2018. The firm expects as much as 50% of this production to come from Cigar Lake. Gitzel said the mine will start producing ore in mid-2013.

Other market uncertainties linger. German utilities have not made their intentions known yet regarding their inventories or long-term contracts.

Despite these developments Gitzel pointed out that the end of the Russian HEU agreement in 2013 would open demand for new production.

But Gitzel worries about the U.S. Department of Energy’s apparent plans to sell new excess uranium inventory into the spot market in the form of re-enriched high-assay tails that are now stored in cylinders at USEC sites. The “evolving situation with USEC” could bring DOE to inject as much as 15-20% of U.S. demand into the market. Gitzel also noted that USEC’s future is tied to political issues in Ohio and to the 2012 presidential election (see related story, below).

Supply Sources Questioned

Asked about development decisions for the Millennium project, Cameo executives said the uranium miner had struck an agreement with AREVA Resources Canada to purchase its 28% interest in the project for $150 million. But the sale of AREVA’s interest depends on whether Japan Canada (JCU) exercises its right of refusal on a portion of the potential transfers to Cameco, according to the terms of its joint-venture agreement with AREVA. JCU’s decision will affect the final number of equity shares, and the size of the stake Cameco will hold in the project.

Asked when the company might make a development decision for the project, Gitzel said a feasibility study is expected this year. But beyond that, Gitzel said, it was too early to comment on a development decision.

Among other things, analysts wondered if Cameco would be able to maintain its 2013-2016 production targets. One pointedly asked whether the uranium colossus would have to obtain material on the market in order to provide product to its customers. Gitzel replied that Cameco would never have to procure material on the market because the company has a six-month supply, roughly 15 million pounds, stockpiled to meet forward sales.

Demand is building, Gitzel said, with growing volumes under long-term contracts even though most demand today is discretionary. The U3O8 spot price for on May 2 was $51.50 per pound, with the U3O8 term price remaining at $60.00 per pound.

Despite Gitzel's confidence in the future of Japan's commercial nuclear energy industry, last week all of its reactors were shut down.  METI minister Yukio Edano, who wants that condition to be permanent, nevertheless is trying to restart them in the short term.  Public opposition is based on broad distrust of the government that trumps technical issues about reactor safety. It's going to be a long hot summer in Japan.

Performance and Financials in a Nutshell

Cameco (TSX:CCO) had a strong first quarter in 2012 with steady production and higher uranium sales volumes.

Revenue increased 22% to C$563 million and net earnings were up 45%, to $132 million. Earnings per share increased 48%, to $0.31. Cash provided by operations increased 54% to $409 million.

Cameco stock closed the day after the earnings announcement, at $23.05, a $0.58 gain, representing a 2.6% rise.

Stock prices ranged the past 12 months from a low of $17.25 to a high of $29.59 with a current market capitalization of $8.92 billion for 394.8 million shares.

Cameco Financials 2012
For three months ending 03/31/12
CDN$M 1Q2012 1Q2011
Revenue 563 461
Gross Profit 178 136
Net Earnings 132 91
Cash from Operations 409 266
Uranium Production (Mlbs) 4.8 4.7
Uranium Sale (Mlbs) 8.1 6.1
Cost of Sales ($/lb) 31.97 32.21
Avg Sale Price ($/lb) 49.40 48.60
Revenue ($M) 401 297
Gross Profiit ($M) 141 100

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Tuesday, May 8, 2012

Reactions to reactor restart remarks about San Onofre

Southern California Edison says no plan submitted to NRC yet

If you've been following the saga of the San Onofre Nuclear Generating Station (SONGS), you know that last week Ron Litzinger, President of Southern California Edison (NYSE:EIX), which owns and operates the twin 1100 MW nuclear reactors, told California's electricity grid operator it may have Unit 2 back online by June 1 and Unit 3 up by June 12.

This week that announcement brought a response in the form of a terse statement from NRC Chairman Gregory Jaczko who said the utility has not submitted any documents for the agency to review "so any discussion of a date for the restart of Unit 2 or Unit 3 is clearly premature." He said the media reports that SCE had given dates for restart are "erroneous."

In fact, there was nothing "erroneous" about the media reports.  Jaczko's problem is that he perceived that the utility was getting out in front of his agency's headlights.  While Jaczko might have reason to worry about the utility CEO's statement, his blunt language in an official agency press release can't have done much for how the utility or the industry views him or expectations for his engagement with the next operationally challenged reactor.

SCE takes a step back

Today, May 8, SCE issued a "clarification" in which it said there is no timeline for restarting the reactor. The utility also said Litzinger's remarks were strictly for "planning purposes" relative to the needs of the grid operator.

"Recent media reports referred to June dates for the restart of Units 2 and 3 at SONGS. However, those dates were provided by SCE to the ISO as a purely administrative matter in March of 2012 because, for long-range planning purposes, ISO requires an estimated return to service date to be posted. These dates are for planning purposes only and are subject to change." 

"We want to clarify the use of planning dates and make sure it is clear that there is no timeline on nuclear safety," said SCE President Ron Litzinger.

ISO is the California Independent System Operator which allocates space on transmission lines, maintains operating reserves of electricity, and matches supply with demand.

Rep. Issa tosses a big rock in a small pond

Rep. Issa
While this series of communications by press release was taking place, in Washington, DC, Rep. Darrell Issa (R-Calif), who's district includes the shut down reactors, released a letter raising the question of whether Jaczko lied to the House Oversight Committee last year when he said he was unaware of instances in which he was accused of losing his temper and bullying the agency’s staff.

Politico, a news service, reported that Issa and other Republicans on the committee, wrote in a letter to the NRC chair citing examples of alleged discrepancies in Jaczko's testimony saying that “making false statements to Congress is a serious matter."

Rep. Issa's timing in terms of the release of the letter over the weekend does not look like a coincidence.

The agency's "confirmatory action letter" is still the roadmap to restart of the San Onofre reactors regardless of what mis-statements Jackzo is alleged to have made, or did not make, to the House Oversight Committee. Paradoxically, Rep. Issa went with Jaczko on his personal inspection of San Onofre last month.

All this must frustrate the socks right off the feet of anti-nuclear groups in California who want the reactors closed for good. Instead of seeing growing support for their cause, the political establishment is doing everything in its power, and then some, to get the reactors working again.

Tubes plugged

In a related development, Reuters reported today that SCE has plugged 1300 tubes in the shut down steam generators. Of that number, 510 tubes have been plugged in Unit 2 and 807 tubes have been plugged in Unit 3.

There are over 9,700 steam tubes in each steam generator for each reactor. SCE has blamed the excessive wear that was found on the relatively new steam generator tubes on vibration which caused them to rub against each other and support structures.

SCE has said that as part of its restart plan that it will eventually submit to the NRC, it may decide to operate the reactors at less than full power. About halfway through the fuel cycle, it would shut down and inspect the steam generators for any signs of additional excessive wear.

SCE has estimated the cost of repairs at $55-65 million and plans to ask Mitsubishi, which installed the stream generators in 2009, to pay them. SCE says so far it has paid $30 million in fuel replacement costs.

The process steps that SONGS must take to re-start the reactors are spelled out in the NRC's  "confirmatory action letter."  SCE published an update on its web site describing what it has done so far. Once SCE completes these actions, the NRC will review them, inspect the plant, the reactors, and, most importantly, the steam generators, to determine if the facility can safely get back to the business of generating electricity instead of headlines.

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Monday, May 7, 2012

Darlington back on the front burner?

Two reactor designs are in the running – again

DoRightCastAnyone who follows the perilous path the future of nuclear energy has taken in Canada’s Ontario province knows that plans to build new nuclear reactors can be announced and shelved on the whims of whatever political party is in office. Never mind that it takes a decade from start to finish to plan, design, license, and build a nuclear reactor.

This time Canada’s current Natural Resources Minister Joe Oliver says he has approved Ontario Power Generation’s plans to build a 4,800 MW expansion of the Darlington nuclear power station near Toronto. His decision, he said, is based on an analysis that it will not cause negative impacts on the environment.

This is good news for the former reactor division of Atomic Energy Canada Ltd (AECL), now owned by SNC Lavalin and which is called Candu Energy.   Also in the running is Westinghouse which will offer its 1100 MW AP1000. 

The project, which was subjected to a multi-panel review by the government, could add up to 4.8 GWe of nuclear generated electricity to the grid.

The next step for Ontario Power is to seek a license from the Canadian Nuclear Safety Commission (CNSC) and select a reactor vendor.

Read the full details exclusively at CoolHandNuke online now.

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