The Japanese government recently announced plans to release into the sea more than 1 million tonnes of radioactive water from the severely damaged Fukushima Daiichi nuclear plant.
The move has sparked global outrage, including from UN Special Rapporteur Baskut Tuncak who recently wrote,
I urge the Japanese government to think twice about its legacy: as a true champion of human rights and the environment, or not.
Alongside our Nobel Peace Prize-winning work promoting nuclear disarmament, we have worked for decades to minimise the health harms of nuclear technology, including site visits to Fukushima since 2011. We’ve concluded Japan’s plan is unsafe, and not based on evidence.
Japan isn’t the only country with a nuclear waste problem. The Australian government wants to send nuclear waste to a site in regional South Australia — a risky plan that has been widely criticised.
Contaminated water in leaking tanks
In 2011, a massive earthquake and tsunami resulted in the meltdown of four large nuclear reactors, and extensive damage to the reactor containment structures and the buildings which house them.
Water must be poured on top of the damaged reactors to keep them cool, but in the process, it becomes highly contaminated. Every day, 170 tonnes of highly contaminated water are added to storage on site.
How does radiation harm marine life?
If radioactive material leaks into the sea, ocean currents can disperse it widely. The radioactivity from Fukushima has already caused widespread contamination of fish caught off the coast, and was even detected in tuna caught off California.
Ionising radiation harms all organisms, causing genetic damage, developmental abnormalities, tumours and reduced fertility and fitness. For tens of kilometres along the coast from the damaged nuclear plant, the diversity and number of organisms have been depleted.
Of particular concern are long-lived radioisotopes (unstable chemical elements) and those which concentrate up the food chain, such as cesium-137 and strontium-90. This can lead to fish being thousands of times more radioactive than the water they swim in.
Failing attempts to de-contaminate the water
In recent years, a water purification system — known as advanced liquid processing — has been used to treat the contaminated water accumulating in Fukushima to try to reduce the 62 most important contaminating radioisotopes.
But it hasn’t been very effective. To date, 72% of the treated water exceeds the regulatory standards. Some treated water has been shown to be almost 20,000 times higher than what’s allowed.
The cherry trees of Fukushima
One important radioisotope not removed in this process is tritium — a radioactive form of hydrogen with a half-life of 12.3 years. This means it takes 12.3 years for half of the radioisotope to decay.
Tritium is a carcinogenic byproduct of nuclear reactors and reprocessing plants, and is routinely released both into the water and air.
The Japanese government and the reactor operator plan to meet regulatory limits for tritium by diluting contaminated water. But this does not reduce the overall amount of radioactivity released into the environment.
How should the water be stored?
The Japanese Citizens Commission for Nuclear Energy is an independent organisation of engineers and researchers. It says once water is treated to reduce all significant isotopes other than tritium, it should be stored in 10,000-tonne tanks on land.
If the water was stored for 120 years, tritium levels would decay to less than 1,000th of the starting amount, and levels of other radioisotopes would also reduce. This is a relatively short and manageable period of time, in terms of nuclear waste.
Then, the water could be safely released into the ocean.
Nuclear waste storage in Australia
Australians currently face our own nuclear waste problems, stemming from our nuclear reactors and rapidly expanding nuclear medicine export business, which produces radioisotopes for medical diagnosis, some treatments, scientific and industrial purposes.
This is what happens at our national nuclear facility at Lucas Heights in Sydney. The vast majority of Australia’s nuclear waste is stored on-site in a dedicated facility, managed by those with the best expertise, and monitored 24/7 by the Australian Federal Police.
But the Australian government plans to change this. It wants to transport and temporarily store nuclear waste at a facility at Kimba, in regional South Australia, for an indeterminate period. We believe the Kimba plan involves unnecessary multiple handling, and shifts the nuclear waste problem onto future generations.
The infrastructure, staff and expertise to manage and monitor radioactive materials in Lucas Heights were developed over decades, with all the resources and emergency services of Australia’s largest city. These capacities cannot be quickly or easily replicated in the remote rural location of Kimba. What’s more, transporting the waste raises the risk of theft and accident.
And in recent months, the CEO of regulator ARPANSA told a senate inquiry there is capacity to store nuclear waste at Lucas Heights for several more decades. This means there’s ample time to properly plan final disposal of the waste.
The Conversation contacted Resources Minister Keith Pitt who insisted the Kimba site will consolidate waste from more than 100 places into a “safe, purpose-built, state-of-the-art facility”. He said a separate, permanent disposal facility will be established for intermediate level waste in a few decades’ time.
Pitt said the government continues to seek involvement of Traditional Owners. He also said the Kimba community voted in favour of the plan. However, the voting process was criticised on a number of grounds, including that it excluded landowners living relatively close to the site, and entirely excluded Barngarla people.
Kicking the can down the road
Both Australia and Japan should look to nations such as Finland, which deals with nuclear waste more responsibly and has studied potential sites for decades. It plans to spend 3.5 billion euros (A$5.8 billion) on a deep geological disposal site.
Intermediate level nuclear waste like that planned to be moved to Kimba contains extremely hazardous materials that must be strictly isolated from people and the environment for at least 10,000 years.
We should take the time needed for an open, inclusive and evidence-based planning process, rather than a quick fix that avoidably contaminates our shared environment and creates more problems than it solves.
It only kicks the can down the road for future generations, and does not constitute responsible radioactive waste management.
The following are additional comments provided by Resources Minister Keith Pitt in response to issues raised in this article (comments added after publication):
(The Kimba plan) will consolidate waste into a single, safe, purpose-built, state-of-the-art facility. It is international best practice and good common sense to do this.
Key indicators which showed the broad community support in Kimba included 62 per cent support in the local community ballot, and 100 per cent support from direct neighbours to the proposed site.
In assessing community support, the government also considered submissions received from across the country and the results of Barngarla Determination Aboriginal Corporation’s own vote.
The vast majority of Australia’s radioactive waste stream is associated with nuclear medicine production that, on average, two in three Australians will benefit from during their lifetime.
The facility will create a new, safe industry for the Kimba community, including 45 jobs in security, operations, administration and environmental monitoring.
Tilman Ruff, Associate Professor, Education and Learning Unit, Nossal Institute for Global Health, School of Population and Global Health, University of Melbourne and Margaret Beavis, Tutor Principles of Clinical Practice Melbourne Medical School
This is an article from I’ve Always Wondered, a new series where readers send in questions they’d like an expert to answer. Send your question to firstname.lastname@example.org
Do underground nuclear tests affect Earth’s tectonic plates, and cause earthquakes or volcanic eruptions? – Anne Carroll, Victoria
Apart from escalating global fears about conflict, North Korea’s recent nuclear tests have raised questions about geological events caused by underground explosions.
So can an underground test cause an earthquake? The short answer is yes: a nuclear explosion can cause small earthquakes. But it is unlikely to affect the earth’s tectonic plates or cause a volcanic eruption.
Although a nuclear explosion releases a lot of energy in the immediate region, the amount of energy is small compared to other stresses on tectonic plates.
What are tectonic plates?
Tectonic plates are slabs of the earth’s crust which move very slowly over the surface of the earth. Mountain ranges form at the edges of the plates when they collide, and ocean basins form when they move apart.
Volcanoes occur mostly where plates are colliding. One plate overrides another, pushing it down to where it may partly melt. The partially melted rock – also known as lava – then rises to the surface, causing a volcano.
The movement of tectonic plates also causes earthquakes, which is why 90% of them occur at the plate boundaries. All but the deepest earthquakes occur along faults, which are breaks in the crust where rocks can move past each other in response to stress. This stress can be from both natural events and human activities.
Human induced earthquakes
“Induced seismicity” is the term used to describe earthquakes caused by human activities.
Human induced earthquakes can be caused by anything that changes the stresses on rocks beneath the surface. These include processes that add or remove great loads from the surface, such as mining, building dams or tall buildings.
Other processes that change the amount of pressure on rocks can include fluid injection from drilling, or extraction of water from aquifers.
Human-induced earthquakes have been reported from every continent except Antarctica. Induced earthquakes only occur where there is already some stress on the rocks. The human activity adds enough stress to the rocks to reach the “tipping point” and trigger the earthquake.
Nuclear explosions can induce small earthquakes along existing faults near a test site. Some underground nuclear tests have fractured the ground surface above the explosions, causing movement on faults adjacent to explosion sites.
Earthquakes from nuclear testing
The 3 September 2017 North Korean nuclear test generated shock waves equivalent to a magnitude 6.3 earthquake. Eight minutes later, a magnitude 4.1 event was detected at the same site. This may have been linked to a collapse of a tunnel related to the blast.
Several small earthquakes measured since the event may have been induced by the nuclear test, but the largest is only a magnitude 3.6. An earthquake of this size would not be felt outside of the immediate area.
The largest induced earthquake ever measured from nuclear testing was a magnitude 4.9 in the Soviet Union. An earthquake of this size can cause damage locally but does not affect the full thickness of the earth’s crust. This means it would not have any effect on the movement of tectonic plates.
Historical data from nuclear testing (mostly in the USA) shows that earthquakes associated with nuclear testing typically occur when the explosion itself measures greater than magnitude 5, 10–70 days after the tests, at depths of less than 5km, and closer than around 15km to the explosion site. More recent studies have concluded that nuclear tests are unlikely to induce earthquakes more than about 50km from the test site.
Concerns have also been raised about the risk of volcanic eruptions induced by the nuclear tests in North Korea. Paektu Mountain is about 100km from the test site and last erupted in 1903.
In the 1970s, the USA conducted a number of nuclear tests in the Aleutian Islands, a volcanic island arc chain containing 62 active volcanoes.
One of the blasts, named Cannikin, was the largest underground nuclear test ever conducted by the USA. There were fears that the blast would cause a huge earthquake and tsunami. The blast did result in some induced earthquakes, but the largest was a magnitude 4.0 and there was no increase in volcanic activity.
Based on this evidence, it seems unlikely a nuclear test by North Korea will trigger an eruption of Paektu Mountain. If the volcano was on the verge of erupting, then an induced earthquake from a nuclear blast could influence the timing of the eruption. However, given the distance from the test site then even this is not likely.
Monitoring nuclear tests
The Comprehensive Nuclear Test Ban Treaty Organisation (CTBTO) has a global monitoring system to detect nuclear tests, including seismometers to measure the shock waves from the blast and other technologies.
Seismologists can analyse the seismic data to determine if the shock waves were from a naturally occurring earthquake or a nuclear blast. Shock waves from nuclear blasts have different properties to those from naturally occurring earthquakes.
Testing was much more common before the CTBTO was formed: between 1945 and 1996 more than 2,000 nuclear tests were conducted worldwide, including 1,032 by the USA and 715 by the Soviet Union.
Since 1996 only three countries have tested nuclear devices: India, Pakistan and North Korea. North Korea has conducted six underground nuclear tests at the same site between 2006 and 2017.
When wetlands flood they become full of life. They are spectacularly beautiful and noisy. There is nothing quite like the sound of a wetland when thousands of birds come together to take advantage of the newly created habitat.
Ibis, spoonbills, egrets, herons, cormorants and pelicans all congregate in large numbers, tens to hundreds of thousands, to breed when wetland conditions are good. These gatherings of birds are spectacular, but a mystery remains: where do they come from, and where do they go?
These questions aren’t trivial. Over the past 30 years waterbird populations have declined as opportunities for breeding have disappeared, mainly due to water resource development.
Worldwide, wetlands have been lost or are under threat from water resource development, agricultural development and climate change. In Australia we have lost an estimated 50% of wetlands since European settlement.
The loss of wetlands has serious implications for wildlife. Many species are wetland-dependent throughout their lives while others, such as some species of waterbirds, rely on wetlands as places to breed.
Knowing which wetlands waterbirds use when they aren’t breeding will help us figure out which places we need to protect. So the Centre for Ecosystem Science, UNSW and the Australian Nuclear Science Technology Organisation have developed a new technique to analyse Australian bird feathers using nuclear physics.
Now we want you to send us waterbird feathers so we can build an Australia-wide map of where our waterbirds go.
Traditional tracking methods such as leg banding and satellite trackers have had limited success and can be expensive. So we looked for a cheaper and more effective method. And what could be easier than collecting bird feathers?
Feathers are made of keratin (the same material as human hair and nails) and as they grow record the diet of the bird in chemical elements. Once fully grown, feathers are inert – they no longer change.
Chemical elements (carbon, nitrogen, hydrogen, oxygen) exist in a number of different forms known as isotopes. Some isotopes of some elements are radioactive, but many elements have stable, non-radioactive isotopes. The relative proportion of different isotopes can be explicitly linked to a specific location, as has been done for monarch butterflies in North America.
To test whether this could be applied to Australian wetlands and waterbirds I did a pilot study in 2010-11. Widespread flooding in the Murray-Darling Basin resulted in colonial waterbirds breeding at a number of wetlands including the Gwydir wetlands, Macquarie Marshes and Lowbidgee wetlands. These three wetlands are geographically distinct, spread across the Basin from north to south.
We used feathers from chicks and juveniles, because they are eating food from only the wetland where they were hatched and so provide a unique signature for that wetland.
We tested the feathers using two techniques: one to look at the elemental composition of feathers, and the other to measure the amount of two particular isotopes, carbon-13 and nitrogen-15.
Results from these analyses showed that we were able to distinguish between the three wetland sites based on the elemental composition of the feather and the isotopic composition.
Either technique showed the ability to distinguish between wetland sites. Combined, they should be able to provide greater spatial accuracy in identifying the wetland at which the feather was grown. With the knowledge that wetlands have their own unique elemental and isotopic signature, we are expanding the study nationally.
Building a ‘feather map’
The Feather Map of Australia is a citizen science project that aims to map the signatures for as many wetlands across Australia as possible. To do this we have asked interested members of the public to collect feathers from their local wetlands and contribute them for analyses.
Once analysed, we will have an isotopic map of wetlands against which we can track waterbird movements. Feathers collected from chicks and birds that don’t move large distances will provide us with a signature for that particular wetland. We can then analyse the feathers of birds that do travel long distances and match the signature in their feathers against those of wetlands, telling us where these birds have been.
The signature will not tell us all the movements a bird has made, but it will tell us where it was when it grew the feather. And this will also give us information about the health of the wetland based on what food the bird has eaten and how long it took to grow the feather.
Knowing the movements of waterbirds helps identify wetlands that are important waterbird habitats. This knowledge can be used to provide information to policymakers and land and water managers for improved water delivery, wetland management and decision-making, and ultimately protect wetlands and waterbirds.
Read more on how to send feathers to scientists and help build the Feather Map of Australia.
The following link is to an article reporting on the latest at the Fukushima Daiichi Nuclear Power Plant in Japan, following the 2011 earthquake and tsunami. The situation is said to be contained, however this would seem to be only to a certain point.
Despite the nuclear problems in Japan following the recent earthquake and tsunami disaster there, consideration still needs to be given to nuclear power as a possible green energy source – certainly I believe that this technology warrants more investigation. The article below raises the possibility of mini-nuclear reactors as being a possible and safer answer to our energy needs.