Tuesday, August 26, 2008

Fears raised over pebble beds

Source: http://www.thetimes.co.za/

A new foreign report casts a further shadow over SA’s troubled nuclear project, but a local research company says there’s no need for alarm. Bobby Jordan reports.

The research centre that invented pebble bed nuclear reactors has rung alarm bells over the safety of the technology — which features prominently in SA’s R350-billion nuclear energy programme.

The safety concerns are contained in a report released this week by the world-renowned state-owned German Jülich Nuclear Research Centre.

Ironically, a team of Jülich researchers is helping SA develop a commercial-size pebble bed reactor based on the prototype that Jülich operated for more than 20 years. If successful, the project could provide much-needed electricity to the local market — and the reactors could be exported worldwide.

Now the latest report, authored by a senior Jülich nuclear safety researcher, casts a further shadow across SA’s beleaguered nuclear project. The report signposts higher-than- anticipated temperatures generated by fuel pebbles used in the prototype reactor (AVR), which was closed in 1988 — but is still the subject of much research.

The chief scientist in charge of exporting Pebble Bed Modular Reactor (PBMR) technology at the Jülich Centre this week denied any crisis of confidence among the nuclear fraternity, and said that although the report was important, it would not undermine confidence in SA’s nuclear energy ambitions. The report has been slated as alarmist by SA’s PBMR company, which is spearheading local research.

PBMR spokesman Tom Ferreira said that although useful, the latest report was “no basis for concern”.

Some of the fears raised in the Jülich report include:

ý The graphite pebbles in the original reactor experiment in Germany generated much more heat than expected, sending temperatures soaring to more than 1450 C — at least 300 degrees hotter than the maximum temperature allowed for in the design of SA’s PBMR;

ý The movement of the pebbles brushing up against one another inside the reactor created a dangerous level of highly radioactive graphite dust — something that was partly unexplained;

ý The risk of graphite fires, like the one at Chernobyl in 1986, cannot be ruled out; and

ý The prototype reactor in Germany is extremely contaminated by metallic fission products, which escaped from fuel elements during operation. The contamination, possibly due to unexpectedly high temperatures, is higher by a factor of more than 10000 than acceptable for modern reactors. This also creates huge decommissioning costs.

The report suggests the SA government may have jumped the gun in pushing for a demonstration PBMR plant at Koeberg, when there is still a need for a prototype pebble bed reactor to understand reasons for high temperatures.

The German report also raises questions about whether senior SA officials have been downplaying safety concerns about pebble bed technology.

Jülich scientists this week confirmed that draft copies of the latest report have been in the possession of SA authorities since December.

So far the pebble bed programme has cost the SA taxpayer about R4-billion, is years behind schedule and is over budget. SA plans to build as many as 30 pebble bed reactors, which collectively would represent about 20% of Eskom’s potential R350-billion nuclear building programme of about 20000 MW. The country’s current mainly coalfired power supply is 39000 MW.

Ferreira said the report was not a consensus position for the Jülich centre. He said many of the points raised in the report were disputed by other scientists.

Tony Stott, Eskom senior manager of Nuclear Stakeholder Management, said: “Eskom is aware of the report and its findings. Eskom has requested independent nuclear consultants, who are assisting Eskom with the safety evaluation of the PBMR Demonstration Power Plant technology, to investigate and establish the basis of the report and determine whether any aspects warrant introduction into the safety evaluation of the technology.”

He said the safety analysis process was still under way.

Source: http://www.thetimes.co.za/

PBMR contract awarded to M&

Published: 22 Aug 08 - 17:16
Source: http://www.engineeringnews.co.za/article.php?a_id=141477

Joint-venture company Murray & Roberts SNC-Lavalin Nuclear (MRSLN) has been awarded the contract for the provision of engineering, procurement, project and construction management (EPCM) services for the Pebble Bed Modular Reactor (PBMR) demonstration plant project at Koeberg, near Cape Town.

The contract for the provision of the EPCM services was signed on Friday, in Pretoria.

The PBMR project entailed the building of both the demonstration reactor project at Koeberg, and a pebble fuel plant at Pelindaba near Pretoria. The current schedule was to start construction in 2010 and for the demonstration plant to be completed by 2014.

“MRSLN's expertise is critical to the success of the demonstration reactor project. While the licencing and environmental impact assessment process for the demonstration power plant still need to be successfully completed, the signing of the EPCM contract represents a significant milestone for PBMR,” said PBMR company CEO Jaco Kriek at the signing ceremony.

He noted that there was increasing international interest in advanced generation IV technology. “Our focus as a company is on developing and using this technology for the benefit of South Africa. We have already achieved many successes in this regard. We have created a large pool of intellectual resources locally and a sizeable company. As the signing of this contract shows, we partner with the best suppliers in the world. Globally, the work we are doing is having a significant impact,” Kriek added.

TSX-listed SNC-Lavalin is said to be one of the leading engineering and construction groups in the world and a major player in the ownership of infrastructure, and in the provision of operations and maintenance services, and is currently working about 100 countries.

Murray & Roberts offers civil, mechanical, electrical, mining and process engineering; general building and construction; materials supply and services to the construction industry; and management of concession operations.

Source: http://www.engineeringnews.co.za/article.php?a_id=141477

Eskom's PBMR Report Delayed

20 August 2008
Source: http://www.bday.co.za/

Siseko Njobeni

THE review of the environmental impact report and public meetings for the Pebble Bed Modular Reactor (PBMR) have been delayed, according to the project's environmental impact assessment consultant.

PBMR, a high temperature reactor with a closed-cycle gas turbine power conversion system, is central to the government's stated desire to diversify electricity generation mix. The PBMR is also central to Eskom's plan to double capacity by 2026.

It was not immediately clear yesterday if the delay would affect the deadlines for the project which has already fallen behind schedule. Construction work for the project was scheduled to commence in 2010.

According to initial forecasts, construction should have started last year and the demonstration plan should be ready by 2011.

In a newspaper advertisement, consultants Arcus Gibb and Acer Africa yesterday announced the delay which they attributed to unspecified "unforeseen circumstances" beyond their control.

The consultant said the report would be made available to the public during the comment period from last Thursday to September 30 in Western Cape, KwaZulu-Natal and Gauteng.

Findings of the draft report and specialist studies were also scheduled to be presented in the three provinces later this month and next month.

The studies for the project are an outcome of work by a team of specialists who looked at issues such as air quality, visual impact, flora, fauna, heritage and archaeology, marine biology, radiological safety and health and seismic risk.

According to the consultants , the project would entail setting up permanent infrastructure. These include an integrated reactor and generator building, a generator and associated electrical power plant, a cooling water plant and a transmission power line.

Dalene Murie of the consultants yesterday referred queries about the delay to Eskom, owners of PBMR. Attempts to get comment from Tony Stott, Eskom senior manager for nuclear stakeholder management, were not successful.

The government has thrown its weight behind the PBMR project. Public Enterprises Minister Alec Erwin has in the past said the government wanted to produce between 4000MW and 5000MW of power from pebble bed reactors.

PBMR was established in 1999 with the intention to develop and market small-scale, high-temperature reactors .

Source: http://www.bday.co.za/

Earthquake Zone Threatens Indian Point Nuke Plant

Source: http://www.ens-newswire.com/ens/aug2008/2008-08-21-01.asp

PALISADES, New York, August 21, 2008 (ENS) - The nuclear power plant closest to America's largest city is more likely to be hit by an earthquake than previously thought because it sits atop a newly identified intersection of two active seismic zones, earthquake scientists warned today.

The Indian Point nuclear power plant, with its two nuclear generating units, is situated 24 miles north of New York City, on the Hudson River at Buchanan, New York.

Researchers from Columbia University's Lamont-Doherty Earth Observatory have located a previously unknown active seismic zone running from Stamford, Connecticut, to the Hudson Valley town of Peekskill, New York, where it passes less than a mile north of the Indian Point nuclear power plant.

The Stamford-Peekskill line intersects with the known Ramapo seismic zone, which runs from eastern Pennsylvania to the mid-Hudson Valley, passing within two miles northwest of Indian Point.

The Stamford-Peekskill line stands out sharply on the researchers' earthquake map, with small events clustered along its length, and to its immediate southwest. Just to the north, there are no quakes, indicating that it represents some kind of underground boundary.

The pattern emerged when the Earth Observatory scientists compiled a catalog of all 383 known earthquakes from 1677 to 2007 in a 15,000 square mile area around New York City. The observatory runs the network of instruments that monitors most of the northeastern United States for earthquake activity.

Their paper appears in the current issue of the "Bulletin of the Seismological Society of America." "Indian Point is situated at the intersection of the two most striking linear features marking the seismicity and also in the midst of a large population that is at risk in case of an accident," says the paper. "This is clearly one of the least favorable sites in our study area from an earthquake hazard and risk perspective."

Lead author Lynn Sykes says the data show that large quakes are infrequent around New York compared to more active areas like California and Japan, but that the risk is high, because of the overwhelming concentration of people and infrastructure.

"The research raises the perception both of how common these events are, and, specifically, where they may occur," he said. "It's an extremely populated area with very large assets."

Nearly 10 million people live within 25 miles of the Indian Point nuclear plant, including the 8.2 million in the New York metropolitan area.

Sykes, who has studied the region for 40 years, is known for his early role in establishing the global theory of plate tectonics.

Sykes and his team say the insight comes from sophisticated analysis of past quakes, plus 34 years of new data on tremors, most of them perceptible only by modern seismic instruments.

It is parallel to other faults beginning at 125th Street in New York City, so the researchers believe it is a fault in the same family. They say it is probably capable of producing at least a magnitude 6 quake, strong enough to damage structures.

Sykes said the existence of the Stamford-Peekskill line had been suggested before, because the Hudson River takes a sudden unexplained bend just to the north of Indian Point, and definite traces of an old fault can be along the north side of the bend.

"The seismic evidence confirms it," he said.

The findings come at a time when Entergy, the owner and operator of Indian Point, is trying to relicense the two operating plants for an additional 20 years - a move being fought by surrounding communities and the New York State Attorney General. Licenses for Indian Point's two reactors expire in 2013 and 2015.

Last fall New York Attorney General Andrew Cuomo, alerted to the then-unpublished Lamont data, told a Nuclear Regulatory Commission panel in a filing, "New data developed in the last 20 years disclose a substantially higher likelihood of significant earthquake activity in the vicinity of [Indian Point] that could exceed the earthquake design for the facility."

The state alleges that Entergy has not presented new data on earthquakes past 1979. However, in a little-noticed decision July 31, the panel rejected the argument on procedural grounds. A source at the attorney general's office said the state is considering its options.

The Earth Observatory research shows a pattern of subtle but active earthquake faults that makes the risk of earthquakes to the entire New York City area greater than scientsts had previously believed.

The evidence charts unseen but potentially powerful structures whose layout and dynamics are only now emerging, say the scientists.

Starting in the early 1970s Lamont began collecting data on quakes from dozens of newly deployed seismometers; these have revealed distinct zones where earthquakes concentrate, and where larger ones could come.

For data on the earlier quakes, coauthor John Armbruster estimated sizes and locations of dozens of events before 1930 by combing newspaper accounts and other records.

His research shows that magnitude 5 quakes - strong enough to cause damage - occurred in 1737, 1783 and 1884.

There was little human settlement in the area to be hurt by the first two quakes, whose locations are vague due to a lack of good accounts; but the 1884 quake, thought to be centered under the seabed somewhere between Brooklyn and Sandy Hook, toppled chimneys across the city and New Jersey, and panicked bathers at Coney Island.

Based on this analysis, the researchers say such quakes should be routinely expected, on average, about every 100 years.

"Today, with so many more buildings and people, a magnitude 5 centered below the city would be extremely attention-getting," said Armbruster. "We'd see billions in damage, with some brick buildings falling. People would probably be killed."

Based on the lengths of the faults, the detected tremors, and calculations of how stresses build in the Earth's crust, the Earth Observatory researchers say that magnitude 6 quakes, or even magnitude 7, are possible.

Source: http://www.ens-newswire.com/ens/aug2008/2008-08-21-01.asp