Open Intelligence / Energy

Any exposure to radioactivity, no matter how slight, boosts cancer risk, according to the National Academy of Sciences. Federal regulators set a limit for how much tritium is allowed in drinking water, where this contaminant poses its main health risk. The U.S. Environmental Protection Agency says tritium should measure no more than 20,000 picocuries per liter in drinking water. The agency estimates seven of 200,000 people who drink such water for decades would develop cancer.

The tritium leaks also have spurred doubts among independent engineers about the reliability of emergency safety systems at the 104 nuclear reactors situated on the 65 sites. That's partly because some of the leaky underground pipes carry water meant to cool a reactor in an emergency shutdown and to prevent a meltdown. Fast moving, tritium can indicate the presence of more powerful radioactive isotopes, like cesium-137 and strontium-90.

So far, federal and industry officials say, the tritium leaks pose no health or safety threat. Tony Pietrangelo, chief nuclear officer of the industry's Nuclear Energy Institute, said impacts are "next to zero." LEAKS ARE PROLIFIC

Like rust under a car, corrosion has propagated for decades along the hard-to-reach, wet underbellies of the reactors — generally built in a burst of construction during the 1960s and 1970s. There were 38 leaks from underground piping between 2000 and 2009, according to an industry document presented at a tritium conference. Nearly two-thirds of the leaks were reported over the latest five years

For example, at the three-unit Browns Ferry complex in Alabama, a valve was mistakenly left open in a storage tank during modifications over the years. When the tank was filled in April 2010, about 1,000 gallons (3,785 liters) of tritium-laden water poured onto the ground at a concentration of 2 million picocuries per liter. In drinking water, that would be 100 times higher than the EPA health standard. And in 2008, 7.5 million picocuries per liter leaked from underground piping at Quad Cities in western Illinois — 375 times the EPA limit.

Subsurface water not only rusts underground pipes, it attacks other buried components, including electrical cables that carry signals to control operations. A 2008 NRC staff memo reported industry data showing 83 failed cables between 21 and 30 years of service - but only 40 within their first 10 years of service. Underground cabling set in concrete can be extraordinarily difficult to replace.

Under NRC rules, tiny concentrations of tritium and other contaminants are routinely released in monitored increments from nuclear plants; leaks from corroded pipes are not permitted. The leaks sometimes go undiscovered for years, the AP found. Many of the pipes or tanks have been patched, and contaminated soil and water have been removed in some places. But leaks are often discovered later from other nearby piping, tanks or vaults. Mistakes and defective material have contributed to some leaks. However, corrosion - from decades of use and deterioration - is the main cause. And, safety engineers say, the rash of leaks suggest nuclear operators are hard put to maintain the decades-old systems.

All countries with well-established nuclear programs have found themselves requiring spent fuel storage in addition to spent fuel pools at reactors. Some, like the US, use dry storage designs, such as individual casks or storage vaults that are located at reactor sites; other countries, Germany for one, use away-from-reactor facilities. Sweden has a large underground pool located at a centralized facility, CLAB, to which different reactors send their spent fuel a year after discharge, so spent fuel does not build up at reactor sites. Dry storage tends to be cheaper and can be more secure than wet storage because active circulation of water is not required. At the same time, because dry storage uses passive air cooling, not the active cooling that is available in a pool to keep the fuel cool, these systems can only accept spent fuel a number of years after discharge.6

The United States had been working toward developing a high-level waste repository at Yucca Mountain, Nevada; this fell through in 2010, when the Obama administration decided to reverse this decision, citing political “stalemate” and lack of public consensus about the site. Instead, the Obama administration instituted the Blue Ribbon Commission on America’s Nuclear Future to rethink the management of the back end of the nuclear fuel cycle.8 The US can flaunt one success, though. The Waste Isolation Pilot Project (WIPP), located near Carlsbad in southern New Mexico, is actually the only operating deep geologic repository for intermediate level nuclear waste, receiving waste since 1998. In the case of WIPP, it only accepts transuranic wastes from the nuclear weapons complex. The site is regulated solely by the Environmental Protection Agency, and the state of New Mexico has partial oversight of WIPP through its permitting authority established by the Resource Conservation and Recovery Act. The city of Carlsbad is supportive of the site and it appears to be tolerated by the rest of the state.9

France has had more success after failing in its first siting attempt in 1990, when a granite site that had been selected drew large protests and the government opted to rethink its approach to nuclear waste disposal entirely. In 2006, the government announced that it needed a geologic repository for high-level waste, identified at least one suitable area, and passed laws requiring a license application to be submitted by 2015 and the site to begin receiving high-level waste by 2025.

Canada recently rethought the siting process for nuclear waste disposal and began a consensus-based participatory process. The Canadian Nuclear Waste Management Organization was established in 2002, after previous attempts to site a repository failed. The siting process began with three years’ worth of conversations with the public on the best method to manage spent fuel. The organization is now beginning to solicit volunteer communities to consider a repository, though much of the process remains to be decided, including the amount and type of compensation given to the participating communities.

the most difficult part of the back end of the fuel cycle is siting the required facilities, especially those associated with spent fuel management and disposal. Siting is not solely a technical problem—it is as much a political and societal issue. And to be successful, it is important to get the technical and the societal and political aspects right.

After weathering the Fukushima accident, and given the current constraints on carbon dioxide emissions and potential for growth of nuclear power, redefinition of a successful nuclear power program is now required: It is no longer simply the safe production of electricity but also the safe, secure, and sustainable lifecycle of nuclear power, from the mining of uranium ores to the disposal of spent nuclear fuel. If this cannot be achieved and is not thought out from the beginning, then the public in many countries will reject nuclear as an energy choice.

Certain elements—including an institution to site, manage, and operate waste facilities—need to be in place to have a successful waste management program. In some countries, this agency is entirely a government entity, such as the Korea Radioactive Waste Management Organization. In other countries, the agency is a corporation established by the nuclear industry, such as SKB in Sweden or Posiva Oy in Finland. Another option would be a public– private agency, such as Spain’s National Company for Radioactive Waste or Switzerland’s National Cooperative for the Disposal of Radioactive Waste.

Funding is one of the most central needs for such an institution to carry out research and development programs; the money would cover siting costs, including compensation packages and resources for local communities to conduct their own analyses of spent fuel and waste transportation, storage, repository construction, operations, security and safeguards, and future liabilities. Funds can be collected in a number of ways, such as putting a levy on electricity charges (as is done in the US) or charging based on the activity or volume of waste (Hearsey et al., 1999). Funds must also be managed—either by a waste management organization or another industry or government agency—in a way that ensures steady and ready access to funds over time. This continued reliable access is necessary for planning into the future for repository operations.

the siting process must be established. This should include decisions on whether to allow a community to veto a site and how long that veto remains operational; the number of sites to be examined in depth prior to site selection and the number of sites that might be required; technical criteria to begin selecting potential sites; non-technical considerations, such as proximity to water resources, population centers, environmentally protected areas, and access to public transportation; the form and amount of compensation to be offered; how the public is invited to participate in the site selection process; and how government at the federal level will be involved.

The above are all considerations in the siting process, but the larger process—how to begin to select sites, whether to seek only volunteers, and so on—must also be determined ahead of time. A short list of technical criteria must be integrated into a process that establishes public consent to go forward, followed by many detailed studies of the site—first on the surface, then at depth. There are distinct advantages to characterizing more than one site in detail, as both Sweden and Finland have done. Multiple sites allow the “best” one to be selected, increasing public approval and comfort with the process.

he site needs to be evaluated against a set of standards established by a government agency in the country. This agency typically is the environmental agency or the nuclear regulatory agency. The type of standards will constrain the method by which a site will be evaluated with regard to its future performance. A number of countries use a combination of methods to evaluate their sites, some acknowledging that the ability to predict processes and events that will occur in a repository decrease rapidly with each year far into the future, so that beyond a few thousand years, little can be said with any accuracy. These countries use what is termed a “safety case,” which includes multiple lines of evidence to assure safe repository performance into the future.

Moving forward

France, Canada, and Germany also have experienced a number of iterations of repository siting, some with more success than others. In the 1970s, Germany selected the Gorleben site for its repository; however, in the late 1990s, with the election of a Red–Green coalition government (the Greens had long opposed Gorleben), a rethinking of repository siting was decreed, and the government established the AkEnd group to re-evaluate the siting process. Their report outlined a detailed siting process starting from scratch, but to date too much political disagreement exists to proceed further.

Notes

Nuclear wastes are classified in various ways, depending on the country or organization doing the classification. The International Atomic Energy Agency (IAEA) notes six general categories of waste produced by civil nuclear power reactors: exempt waste, very short-lived waste, and very low level waste can be stored and then disposed of in landfill-type settings; low level waste, intermediate level waste, and high-level waste require more complex facilities for disposal.

Sweden is currently the country closest to realizing a final solution for spent fuel, after having submitted a license application for construction of a geologic repository in March 2011. It plans to open a high-level waste repository sometime after 2025, as do Finland and France.

Some countries, such as Sweden, Finland, Canada, and, until recently, the US, plan to dispose of their spent fuel directly in a geologic repository. A few others, such as France, Japan, Russia, and the UK have an interim step. They reprocess their spent fuel, extract the small amount of plutonium produced during irradiation, and use it in new mixed oxide (MOX) fuel. Then they plan to dispose of the high-level wastes from reprocessing in a repository.

Regulatory changes    The size, budget and capability of the Chinese regulatory system should grow dramatically. It is currently overseen by a staff of 30-40 at the National Nuclear Safety Administration, with support from the Nuclear and Radiation Safety Centre's 200 technical experts. Inspection of power plants and equipment suppliers, as well as radiation monitoring, is undertaken by six regional centres.   This set-up runs on a budget that is a tiny fraction of parallel regimes in other countries - and some budgetary areas have not been growing at the same speed as reactor build, said Zhou.   Overall, she considered the system "on a par with global standards." But while there exists the proper strong safety culture, led from the top of the regime, there is a "lack of experience and technical capability to identify the technical issues," which has manifested itself in some construction delays.

TEPCO said most of the accumulated hydrogen was generated by a reaction under high temperatures between water vapor and the surface of nuclear fuel rods that were exposed after water was lost following the March 11 earthquake and tsunami. Even now, the damaged reactors may be generating small amounts of hydrogen as water decomposes through irradiation from the melted fuel rods.

At Fukushima I Nuclear Power Plant, the Reactor 1 reactor building blew up in a hydrogen explosion in the afternoon of March 12, followed by a hydrogen explosion of Reactor 3 in the morning of March 14. Further, in the early morning on March 15, there was an explosive sound, and the damage to the Reactor 4 reactor building was confirmed. Right after the explosive sound the pressure in the Suppression Chamber of Reactor 2 dropped sharply, which led TEPCO to conclude that there were near-simultaneous explosions in Reactors 2 and 4. The Japanese government reported the events as such in the report to IAEA in June.So then what does TEPCO now think happened in Reactor 2 in the early morning on March 15? Yomiuri doesn't say in the article text, but at the bottom of the illustration that accompanies the article it says:"There was no explosion, but a possibility of some kind of damage to the Containment Vessel."So, before TEPCO completely changes story, here's what they say happened on Reactor 4 on March 15 (from the daily "Status of TEPCO's Facilities - past progress" report, page 6):

It says "abnormal sound was confirmed near the suppression chamber" at 6:14AM on March 15.Now, this is what TEPCO says about Reactor 4 on the same day, about the same time, from Page 16:

It says "an explosive sound was heard" at 6AM on March 15. The Reactor 4 explosion occurred before the Reactor 2 "explosion" which TEPCO now says never happened.The two sounds are 14 minutes apart, and TEPCO now claims they misheard the second one and there was no explosion in the Suppression Chamber of Reactor 2.(By the way, the fire spotted at 9:38AM on March 15 on Reactor 4 was never reported to the local fire department or the local government, as I reported on March 15.)

The opposition has focused mainly on imported reactors, the designs of which are untried. "The French reactor offered to India is not working anywhere in the world and the Russian reactor had to undergo several design changes before we accepted it," says Annaswamy Prasad, retired director of the Bhabha Atomic Research Centre in Mumbai. "If any accident happens in India it will be in imported reactor and not in our home-made pressurized heavy water reactors" (PHWRs), he adds.

Ideally, says Prasad, India should boost its nuclear capacity by building more PHWRs fuelled by natural uranium, instead of importing reactors that require enriched uranium. Although the foreign vendors have agreed to supply fuel for the lifetime of their reactors, overreliance on imports will derail India's home-grown programme, the Bhabha scheme, he warns.

The Bhabha scheme involves building PHWRs, which would produce enough plutonium as a by-product to fuel fast-breeder reactors that would in turn convert thorium — which is abundantly available in India — into fissile uranium-233. In the third and final phase, India hopes to run its reactors using the 233U–Th cycle without any need for new uranium. Gopalakrishnan says that building indigenous reactors is not enough: the country must also invest in renewable energy sources, such as wind and solar power. But a survey by Subhas Sukhatme, a former chairman of the Atomic Energy Regulatory Board, warns that India's renewable energy sources, even stretched to their full potential, can at best supply 36.1% of the country's total energy needs by the year 2070. The balance would have to come from fossil fuels and nuclear energy. 

The study was commissioned by the Low Carbon Vehicle Partnership, which is jointly funded by the British government and the car industry. It found that a mid-size electric car would produce 23.1 tonnes of CO2 over its lifetime, compared with 24 tonnes for a similar petrol car. Emissions from manufacturing electric cars are at least 50 per cent higher because batteries are made from materials such as lithium, copper and refined silicon, which require much energy to be processed.

Many electric cars are expected to need a replacement battery after a few years. Once the emissions from producing the second battery are added in, the total CO2 from producing an electric car rises to 12.6 tonnes, compared with 5.6 tonnes for a petrol car. Disposal also produces double the emissions because of the energy consumed in recovering and recycling metals in the battery. The study also took into account carbon emitted to generate the grid electricity consumed.