0:00:06 > 0:00:10Fukushima, north-east Japan.
0:00:11 > 0:00:14This is as close as you can get
0:00:14 > 0:00:19to the site of a partial nuclear meltdown six months ago.
0:00:21 > 0:00:27But the events still unfolding here have consequences for us all.
0:00:30 > 0:00:34Energy is the lifeblood of our civilization.
0:00:34 > 0:00:37But where it comes from and how we get
0:00:37 > 0:00:39is something that touches all our lives.
0:00:39 > 0:00:44It's also, I think, one of the most important questions for science.
0:00:49 > 0:00:52We all need an energy supply that's reliable,
0:00:52 > 0:00:55but it also has to be safe.
0:01:01 > 0:01:04Around the world, many questions are now being asked
0:01:04 > 0:01:06about nuclear power.
0:01:08 > 0:01:11Some countries are looking to abandon it,
0:01:11 > 0:01:16but what lessons should we learn from the events at Fukushima?
0:01:37 > 0:01:40What I love most about Tokyo is the night-time.
0:01:40 > 0:01:44That's when the city comes alive with such energy,
0:01:44 > 0:01:46that's when it glows so brightly.
0:01:46 > 0:01:49But it's not glowing so brightly tonight.
0:01:49 > 0:01:53Things just don't look the way they normally do.
0:02:02 > 0:02:07By night, unnecessary lights are turned off.
0:02:09 > 0:02:14By day, machines stand stationary.
0:02:14 > 0:02:18And people resist turning on their air conditioning.
0:02:26 > 0:02:28A country for whom using energy
0:02:28 > 0:02:32has become as natural as breathing air,
0:02:32 > 0:02:34suddenly, very uncomfortably,
0:02:34 > 0:02:35must hold its breath.
0:02:39 > 0:02:44And that's because since the earthquake and tsunami struck
0:02:44 > 0:02:46over 100 miles away,
0:02:46 > 0:02:49electricity use has been rationed here.
0:02:51 > 0:02:55Here in Japan, the mood has turned against nuclear power.
0:02:57 > 0:02:59You can understand why.
0:02:59 > 0:03:01But is that the right reaction?
0:03:06 > 0:03:08I'm a professor of nuclear physics,
0:03:08 > 0:03:10but I have no agenda,
0:03:10 > 0:03:11no axe to grind.
0:03:11 > 0:03:15I'm not in the pay of the nuclear industry,
0:03:15 > 0:03:18nor the environmental movement.
0:03:18 > 0:03:21Let me lay my cards on the table.
0:03:21 > 0:03:25I've always believed that nuclear power is a good thing.
0:03:25 > 0:03:29It provides vast amounts of cheap and reliable energy.
0:03:29 > 0:03:32But I want to see how it's running, out in the real world.
0:03:32 > 0:03:34How reliable is it?
0:03:34 > 0:03:36How safe is it?
0:03:36 > 0:03:39I want to leave the politics and economics to one side
0:03:39 > 0:03:42and focus only on the science.
0:03:42 > 0:03:44After all, I am a scientist.
0:03:44 > 0:03:47But I'm also a husband and a father,
0:03:47 > 0:03:52and I want to know what's the safest option for my family's future,
0:03:52 > 0:03:53just like you.
0:04:03 > 0:04:06I want to start by going to the heart of the place
0:04:06 > 0:04:10that has shattered many people's confidence -
0:04:10 > 0:04:12Fukushima.
0:04:22 > 0:04:24Soon after the Tsunami struck,
0:04:24 > 0:04:28news spread that the nuclear power station had been damaged.
0:04:28 > 0:04:31There was a partial meltdown in one,
0:04:31 > 0:04:34and possibly three of the reactors.
0:04:34 > 0:04:37The situation appeared to be running out of control.
0:04:39 > 0:04:44Very rapidly, the perception of nuclear power began to change
0:04:44 > 0:04:47and governments reacted.
0:04:50 > 0:04:52The German's have said
0:04:52 > 0:04:56they'll shut down their nuclear reactors by 2022.
0:04:58 > 0:04:59The Swiss announced
0:04:59 > 0:05:03that none of their existing nuclear plants would be replaced.
0:05:05 > 0:05:06A referendum in Italy
0:05:06 > 0:05:10rejected plans to return to nuclear power generation.
0:05:10 > 0:05:16And an explosion at a nuclear reprocessing plant in France two days ago
0:05:16 > 0:05:20will only have stoked these fears further.
0:05:20 > 0:05:22For the past few years,
0:05:22 > 0:05:25there'd been talk of a Nuclear Renaissance.
0:05:25 > 0:05:27Not any more.
0:05:32 > 0:05:37I've come here to separate fact from emotion,
0:05:37 > 0:05:39to see the reality for myself.
0:05:39 > 0:05:43I want answers to a couple of questions.
0:05:43 > 0:05:45Firstly, just how bad was it,
0:05:45 > 0:05:47what was the human impact?
0:05:47 > 0:05:48And secondly,
0:05:48 > 0:05:52how lasting is the damage really likely to be?
0:05:56 > 0:05:59But first, I'm heading to the exclusion zone,
0:05:59 > 0:06:03which is as close as I can get to the plant.
0:06:11 > 0:06:15'Hours after the first explosion at the power station,
0:06:15 > 0:06:18'this evacuation zone was set up.'
0:06:22 > 0:06:26Well, ahead of me are some guards blocking the road.
0:06:26 > 0:06:29They look like they mean business.
0:06:31 > 0:06:35'Eventually, anyone living within a 20km radius of the plant
0:06:35 > 0:06:39'was evacuated from their homes.
0:06:39 > 0:06:41'Nearly 80,000 people.'
0:06:44 > 0:06:47Well, the clean-up operation carries on at the plant
0:06:47 > 0:06:51and these are returning workers...
0:06:53 > 0:06:56..who are just coming out of the exclusion zone.
0:06:56 > 0:07:00And this is, essentially, the boundary, this is the border.
0:07:00 > 0:07:04Beyond it, 20km in that way,
0:07:04 > 0:07:06is the Fukushima nuclear plant.
0:07:07 > 0:07:10But what is striking
0:07:10 > 0:07:12is that for 20km in that direction
0:07:12 > 0:07:17and a further 20km down the coast, beyond the plant,
0:07:17 > 0:07:19is complete emptiness.
0:07:19 > 0:07:21Apart from the nuclear workers,
0:07:21 > 0:07:22no-one is allowed in,
0:07:22 > 0:07:24no-one lives there any more.
0:07:24 > 0:07:28That's a lot of empty space for a country as crowded as Japan.
0:07:31 > 0:07:33'But what happened to cause this?'
0:07:44 > 0:07:49We can't get inside the Fukushima Daiichi plant,
0:07:49 > 0:07:50but in May this year,
0:07:50 > 0:07:53an international group of scientists
0:07:53 > 0:07:56went inside to investigate what went wrong.
0:08:04 > 0:08:06There's now a well-established story
0:08:06 > 0:08:11of what happened at the Fukushima Daiichi nuclear plant on March 11th.
0:08:11 > 0:08:12First, the earthquake hit,
0:08:12 > 0:08:14followed by the tsunami,
0:08:14 > 0:08:17wiping out the vital power supply
0:08:17 > 0:08:20needed to cool the reactors once they shut down.
0:08:20 > 0:08:22And they did shut down.
0:08:24 > 0:08:28This is the moment the tsunami struck the power station.
0:08:31 > 0:08:33As the 14-metre wave hit,
0:08:33 > 0:08:37it overwhelmed the sea wall,
0:08:37 > 0:08:39and swamped the diesel pumps.
0:08:42 > 0:08:43The resulting loss of power
0:08:43 > 0:08:46shut off cooling to the reactors.
0:08:49 > 0:08:52This was crucial,
0:08:52 > 0:08:55because even though the reactors were shut down,
0:08:55 > 0:08:57they were still generating heat.
0:08:58 > 0:09:03Heat remained within the reactors and they slowly started to cook.
0:09:03 > 0:09:08This led ultimately to the build-up of pressure and explosions.
0:09:08 > 0:09:11Not nuclear explosions, but gas explosions.
0:09:11 > 0:09:15Accompanied by them was the release of radioactive particles
0:09:15 > 0:09:17out into the atmosphere.
0:09:23 > 0:09:26There was a release of steam and radioactive material,
0:09:26 > 0:09:30including isotopes of caesium and iodine.
0:09:30 > 0:09:34But there was perhaps a less well-known part of the design
0:09:34 > 0:09:38which contributed to the explosions.
0:09:38 > 0:09:39To understand why,
0:09:39 > 0:09:44it's helpful to understand how a nuclear reactor works.
0:09:47 > 0:09:51The science behind nuclear power is actually quite simple.
0:09:51 > 0:09:55At the heart of a nuclear plant are pellets like these,
0:09:55 > 0:09:57called fuel pellets.
0:09:57 > 0:10:00They contain radioactive uranium.
0:10:00 > 0:10:04Now, the way the energy is released
0:10:04 > 0:10:07is when the nucleus of a uranium atom
0:10:07 > 0:10:09is hit by a neutron.
0:10:09 > 0:10:14Now, this splits the uranium nucleus in two, releasing energy.
0:10:15 > 0:10:18But it also releases two or three other neutrons,
0:10:18 > 0:10:23and these fly off and hit further uranium nuclei,
0:10:23 > 0:10:26forcing them to split as well.
0:10:26 > 0:10:29This process is called a controlled chain reaction.
0:10:30 > 0:10:35This all takes place inside zirconium cylinders like this.
0:10:35 > 0:10:37These contain the fuel pellets.
0:10:37 > 0:10:40As the chain reaction goes on inside, releasing energy,
0:10:40 > 0:10:43these fuel rods heat up.
0:10:43 > 0:10:47Essentially, they act just like the elements of a kettle.
0:10:47 > 0:10:50Just like in a kettle, they're surrounded by water,
0:10:50 > 0:10:53which they heat up, turn to steam,
0:10:53 > 0:10:57which is used to drive turbines that generate electricity.
0:10:57 > 0:11:00Now, it's the same in a nuclear power plant,
0:11:00 > 0:11:03just as it is in any other type of power plant.
0:11:03 > 0:11:06They're all essentially giant kettles.
0:11:09 > 0:11:12At Fukushima, when cooling was lost,
0:11:12 > 0:11:16the zirconium fuel rods began to overheat.
0:11:16 > 0:11:19They reacted with steam around them
0:11:19 > 0:11:22and produced hydrogen.
0:11:23 > 0:11:26This was vented out into the reactor building
0:11:26 > 0:11:28where it mixed it with oxygen...
0:11:29 > 0:11:30and exploded.
0:11:37 > 0:11:39Now, the reason part of the design
0:11:39 > 0:11:44of this particular variety of boiling-water reactor at Fukushima
0:11:44 > 0:11:46might have contributed to the sequence of events,
0:11:46 > 0:11:49is because it made it harder
0:11:49 > 0:11:53to deal with the steam building up in the reactor.
0:11:54 > 0:11:57Let me explain. In a boiling-water reactor,
0:11:57 > 0:12:02the reactor is connected to a condensation chamber
0:12:02 > 0:12:05which acts as relief for some of the steam.
0:12:05 > 0:12:08Now, in an old reactor like Fukushima's,
0:12:08 > 0:12:12this condensation chamber was probably too small.
0:12:12 > 0:12:14Had it been larger in size,
0:12:14 > 0:12:17it would have been able to cope with more of the steam,
0:12:17 > 0:12:22giving the safety workers crucial time to deal with the problem.
0:12:28 > 0:12:30This was an old nuclear plant,
0:12:30 > 0:12:32commissioned around 40 years ago,
0:12:32 > 0:12:36but even though there was a partial meltdown here,
0:12:36 > 0:12:41much of the radiation was kept inside the plant.
0:12:46 > 0:12:49The thing about the accident that happened here
0:12:49 > 0:12:51is that we can find reasons for it -
0:12:51 > 0:12:53the well-told story
0:12:53 > 0:12:57that the sea wall wasn't built high enough to withstand the tsunami.
0:12:57 > 0:13:01But the thing about the failure of this nuclear plant
0:13:01 > 0:13:03is that it was an old nuclear plant,
0:13:03 > 0:13:05old in design, old in technology.
0:13:05 > 0:13:07And where you look elsewhere
0:13:07 > 0:13:10at nuclear power stations of a similar age,
0:13:10 > 0:13:16they've mostly been either retired off or upgraded.
0:13:18 > 0:13:21Understandably, many countries around the world
0:13:21 > 0:13:23are now examining the safety of their reactors,
0:13:23 > 0:13:28but I believe we should be careful not to make a blanket judgment
0:13:28 > 0:13:31about all nuclear power
0:13:31 > 0:13:33on the basis of what happened here.
0:13:43 > 0:13:47But the people here still need to deal with the consequences.
0:13:51 > 0:13:55This gym in Minamisoma is today serving as a meeting point
0:13:55 > 0:13:58for some of the people forced from their homes.
0:14:00 > 0:14:05Today is the first time they've been into the exclusion zone
0:14:05 > 0:14:06since it was created.
0:14:19 > 0:14:22A route is planned to take them home.
0:14:24 > 0:14:26They must wear dose meters
0:14:26 > 0:14:30and there's a strict time limit of two hours.
0:14:31 > 0:14:35How do you feel about today? Are you excited? Are you nervous?
0:14:35 > 0:14:37TRANSLATION FROM JAPANESE:
0:14:44 > 0:14:46We aren't allowed into the zone,
0:14:46 > 0:14:49so former resident Kunitomo Tokuzawa
0:14:49 > 0:14:51is taking a camera for us
0:14:51 > 0:14:54to chart his trip back home with his mother.
0:15:00 > 0:15:02Two hours later,
0:15:02 > 0:15:06everyone returns with their carefully selected belongings.
0:15:06 > 0:15:09They're allowed to bring out just one bagful,
0:15:09 > 0:15:12measuring 70cm by 70cm.
0:15:14 > 0:15:16TRANSLATION FROM JAPANESE:
0:15:34 > 0:15:36'Kunitomo returns with the camera
0:15:36 > 0:15:39'and a glimpse into an abandoned world.'
0:15:39 > 0:15:43Good to see. OK, well, come and tell me all about it.
0:18:11 > 0:18:16No-one knows when these people will be allowed to return to their homes, if ever.
0:18:18 > 0:18:23Many have been forced to move to a new city in search of work.
0:18:23 > 0:18:28And for a disturbing number, their lives are still in limbo.
0:18:38 > 0:18:42Nearby is Haramachi Junior High School.
0:18:49 > 0:18:53But for now, it's also serving as an emergency evacuation centre
0:18:53 > 0:18:56for those who were living close to the nuclear plant.
0:18:56 > 0:18:58Konichiwa.
0:18:58 > 0:19:04I met Shizuo Konno, an evacuee whose home is now a classroom floor.
0:19:04 > 0:19:07Your home is just a few miles away.
0:19:07 > 0:19:10How frustrating must this be for you?
0:19:13 > 0:19:15TRANSLATION FROM JAPANESE:
0:19:26 > 0:19:27Are you angry
0:19:27 > 0:19:31with the way the situation has been dealt with,
0:19:31 > 0:19:33making you leave your home?
0:19:57 > 0:20:00Arigato.
0:20:00 > 0:20:05Shizuo is facing up to the fact that he may never work on his farm again.
0:20:11 > 0:20:15I caught up with the director of the evacuation centre, Iwao Hoshi.
0:20:18 > 0:20:21So how many people are actually living now
0:20:21 > 0:20:23in this evacuation centre?
0:20:23 > 0:20:26TRANSLATION FROM JAPANESE:
0:20:38 > 0:20:39And thousands of people
0:20:39 > 0:20:43still remain in temporary and makeshift accommodation.
0:20:49 > 0:20:53You know, some of the stories I've heard today have been heartbreaking
0:20:53 > 0:20:55and it's quite tragic to think
0:20:55 > 0:20:57that there are tens of thousands of other stories
0:20:57 > 0:20:59just like the ones I heard.
0:20:59 > 0:21:02But let's get things into perspective.
0:21:02 > 0:21:06The earthquake and tsunami killed over 20,000 people.
0:21:06 > 0:21:10No-one has died as a result of the fall-out from the nuclear plant.
0:21:15 > 0:21:19The International Atomic Energy Agency have said that, to date,
0:21:19 > 0:21:23no confirmed long-term health effects to any person
0:21:23 > 0:21:27have been reported as a result of radiation exposure.
0:21:27 > 0:21:31Around 30 workers were exposed to high doses initially,
0:21:31 > 0:21:35and for these people, there may be a small percentage increase
0:21:35 > 0:21:39in their risk of eventually incurring some health effects.
0:21:53 > 0:21:57I'm in Japan, four months after the tsunami struck the plant.
0:22:00 > 0:22:02What remains of the radiation now?
0:22:04 > 0:22:07And does it justify the exclusion zone?
0:22:16 > 0:22:19This is the village of Iitate,
0:22:19 > 0:22:23population usually 6,165.
0:22:26 > 0:22:28But it's been completely evacuated,
0:22:28 > 0:22:31even though it's outside the exclusion zone.
0:22:35 > 0:22:39That's because radioactive particles from the Fukushima reactor
0:22:39 > 0:22:42have been carried here by the weather.
0:22:42 > 0:22:47Now it's entirely abandoned.
0:22:47 > 0:22:52Every house, every street...
0:22:52 > 0:22:54even this school.
0:23:00 > 0:23:04I've come here today to witness something I've never seen before.
0:23:04 > 0:23:05In fact, it's an event
0:23:05 > 0:23:08that's only happened a few times during my lifetime,
0:23:08 > 0:23:12and that's part of a radioactive clean-up operation.
0:23:12 > 0:23:15And so, as a precautionary measure,
0:23:15 > 0:23:17I'm wearing these wellington boots,
0:23:17 > 0:23:19just to make sure that I don't get any contamination
0:23:19 > 0:23:23from any dust on the ground
0:23:23 > 0:23:25as I walk around.
0:23:31 > 0:23:35Today, scientists from Fukushima University
0:23:35 > 0:23:38will take measurements of the soil,
0:23:38 > 0:23:43which is where most, or all, of the radioactive particles will be now,
0:23:43 > 0:23:46because they've fallen from the air to the ground.
0:23:46 > 0:23:49They're looking for two toxic elements
0:23:49 > 0:23:51which escaped from Fukushima.
0:23:51 > 0:23:54In particular, radioactive iodine
0:23:54 > 0:23:56and radioactive caesium.
0:23:59 > 0:24:03But one of these elements, radioactive iodine,
0:24:03 > 0:24:04is only present for a short time.
0:24:08 > 0:24:12TRANSLATION FROM JAPANESE: Right now, because about four months has passed,
0:24:12 > 0:24:14I predict the iodine has disappeared.
0:24:14 > 0:24:20And that's because radioactive elements decay over time,
0:24:20 > 0:24:24eventually changing into stable, non-radioactive forms.
0:24:24 > 0:24:27It's the half-life of an element
0:24:27 > 0:24:30that's a good measure of how quickly this happens.
0:24:32 > 0:24:36TRANSLATION: So, only traces of caesium 137 and 134
0:24:36 > 0:24:38are being detected.
0:24:38 > 0:24:43So, there will only be caesium in the soil.
0:24:43 > 0:24:46How dangerous is this? How long will it remain in the ground?
0:24:46 > 0:24:53TRANSLATION: The half-life of caesium is said to be close to 30 years.
0:24:53 > 0:24:56So, for a long time, caesium will be the biggest problem.
0:24:58 > 0:25:03Back in the lab, they've found high levels of radiation
0:25:03 > 0:25:06in the top 2.5 centimetres of the soil.
0:25:06 > 0:25:08Other studies from nearby
0:25:08 > 0:25:13found levels more than 500 times higher than normal.
0:25:13 > 0:25:17Removing this topsoil here would be an expensive option
0:25:17 > 0:25:21and Iitate isn't even in the exclusion zone.
0:25:27 > 0:25:29Recently, the Japanese Government
0:25:29 > 0:25:32has been monitoring the radiation level
0:25:32 > 0:25:35across 50 sites inside the zone.
0:25:36 > 0:25:41They've set their safety limit at 20 millisieverts per year,
0:25:41 > 0:25:42which is the same limit
0:25:42 > 0:25:45as for people working in the nuclear industry in the UK.
0:25:47 > 0:25:51What they've found is that 35 of the sites exceeded this level
0:25:51 > 0:25:56and the highest reading was 500 millisieverts.
0:26:03 > 0:26:08The tests will help decide whether these people can go home.
0:26:08 > 0:26:13The government has decided to keep the exclusion zone in place,
0:26:13 > 0:26:17but that's a more complex decision than it looks.
0:26:19 > 0:26:20For perspective,
0:26:20 > 0:26:22you'd get around that level,
0:26:22 > 0:26:2420 millisieverts a year,
0:26:24 > 0:26:27from two CT scans per year.
0:26:29 > 0:26:32On one hand, setting such a limit
0:26:32 > 0:26:34protects people's health effectively,
0:26:34 > 0:26:37but on the other, that comes at a cost -
0:26:37 > 0:26:42the upheaval of 78,000 lives.
0:26:51 > 0:26:53So let's take stock.
0:26:53 > 0:26:55Certainly, governments around the world
0:26:55 > 0:26:58are looking to Japan to help them make a decision.
0:26:58 > 0:27:00Of course, they're going to be influenced by the fact
0:27:00 > 0:27:03that tens of thousands of people had to be evacuated,
0:27:03 > 0:27:07and that the exclusion zone carries with it an economic cost,
0:27:07 > 0:27:08as well as the human one.
0:27:08 > 0:27:11But it's also true
0:27:11 > 0:27:16that the containment process around the reactor largely worked.
0:27:16 > 0:27:18Most of the radiation was kept in,
0:27:18 > 0:27:23which is pretty remarkable for such an old and flawed reactor.
0:27:23 > 0:27:26And, most importantly, no-one died.
0:27:26 > 0:27:31And there have been no associated radiation health risks so far.
0:27:35 > 0:27:38One of the questions that Fukushima raises is this -
0:27:38 > 0:27:44how do we judge what level of radiation can be considered safe?
0:27:44 > 0:27:48This question has been relevant to one place in particular -
0:27:48 > 0:27:52the site of the biggest nuclear accident in history.
0:28:12 > 0:28:14Pripyat.
0:28:14 > 0:28:19A ruined and deserted city in the former Soviet Union.
0:28:23 > 0:28:25On 26th April 1986,
0:28:25 > 0:28:29three kilometres away at the Chernobyl power plant,
0:28:29 > 0:28:30a reactor exploded...
0:28:32 > 0:28:35releasing three tonnes of nuclear fuel.
0:28:38 > 0:28:4128 of the workers who were first on the scene
0:28:41 > 0:28:44received extremely high doses of radiation
0:28:44 > 0:28:47and died within four months.
0:28:51 > 0:28:54But there's another question I'm interested in.
0:28:54 > 0:28:58What was the effect of the radiation released on another group -
0:28:58 > 0:29:02not those working at the site or helping with the clean-up,
0:29:02 > 0:29:04but the general population living here?
0:29:06 > 0:29:10Galina Chayka was among those living in Pripyat
0:29:10 > 0:29:14at the time of the Chernobyl accident.
0:29:14 > 0:29:19Today she's returning to her home for the first time in 25 years.
0:29:22 > 0:29:25TRANSLATION: Here is our entrance.
0:29:26 > 0:29:28And here is the door.
0:29:28 > 0:29:33Now everything is broken, nothing is left.
0:29:35 > 0:29:39Oh, my flat, meet me 25 years after!
0:29:55 > 0:29:57When the accident happened,
0:29:57 > 0:30:01Galina and her children were there to witness it.
0:30:06 > 0:30:09TRANSLATION: We went out and watched it,
0:30:09 > 0:30:12how the reactor was burning like Bengal fires,
0:30:12 > 0:30:15and kids climbed the roofs and watched it,
0:30:15 > 0:30:19until somebody said it was dangerous and made us stay inside.
0:30:21 > 0:30:26They weren't evacuated for another two days.
0:30:26 > 0:30:31Galina believes that the accident's impact began soon after.
0:30:33 > 0:30:37TRANSLATION: Soon after the accident I started to have headaches,
0:30:37 > 0:30:39terrible headaches.
0:30:39 > 0:30:42I got high blood pressure, heart problems,
0:30:42 > 0:30:46my stomach started to hurt because of all the nerves,
0:30:46 > 0:30:49and maybe I've got some sort of radiation.
0:30:55 > 0:30:59It's a situation that constantly occupies her mind.
0:31:03 > 0:31:06TRANSLATION: Now I mostly live in fear of poor health,
0:31:06 > 0:31:09disease, illnesses, death.
0:31:09 > 0:31:12You live in fear every day
0:31:12 > 0:31:16that today you are alive, and tomorrow you get ill.
0:31:16 > 0:31:17This is the everyday fear.
0:31:24 > 0:31:27Galina is not alone.
0:31:27 > 0:31:31Many more people share the same fears.
0:31:31 > 0:31:34But it's difficult, scientifically,
0:31:34 > 0:31:38to show a link between any one person's illness
0:31:38 > 0:31:40and their exposure to radiation.
0:31:43 > 0:31:46But, 20 years after the accident,
0:31:46 > 0:31:48a large-scale international project,
0:31:48 > 0:31:50the Chernobyl Forum,
0:31:50 > 0:31:54set out to understand the impact of the release of this radiation.
0:31:59 > 0:32:02I've come to meet Professor Mykola Tronko,
0:32:02 > 0:32:07who is in charge of the Institute of Endocrinology here in the Ukraine.
0:32:09 > 0:32:12Initially, many doctors expected Chernobyl
0:32:12 > 0:32:17to cause different types of cancer in hundreds of thousands of people.
0:32:17 > 0:32:20But what actually happened was very different.
0:32:23 > 0:32:26TRANSLATION: Starting from 1990,
0:32:26 > 0:32:30we saw the increase of thyroid cancer incidents among children.
0:32:30 > 0:32:35It certainly caused a big discussion in the scientific world.
0:32:37 > 0:32:41'Despite this wave of cases of thyroid cancer,
0:32:41 > 0:32:45'there were no confirmed increases in any other type of cancer
0:32:45 > 0:32:46'in the general population.'
0:32:50 > 0:32:52TRANSLATION: We can say that problem number one,
0:32:52 > 0:32:56as far as the medical effects of the Chernobyl accident are concerned,
0:32:56 > 0:32:58is the problem of pathologies of the thyroid gland,
0:32:58 > 0:33:01particularly thyroid cancer.
0:33:02 > 0:33:04How many thousands of people
0:33:04 > 0:33:08have been diagnosed as having thyroid cancer,
0:33:08 > 0:33:12as a result - as far as you can understand - of the accident itself?
0:33:12 > 0:33:16TRANSLATION: For all cases of thyroid cancer,
0:33:16 > 0:33:20the institute has a register of patients who were operated on
0:33:20 > 0:33:22for thyroid cancer.
0:33:22 > 0:33:29In this register, 2,000 - 2,500 refer to radio-induced thyroid cancer.
0:33:34 > 0:33:39The thyroids were removed, studied and stored here.
0:33:42 > 0:33:46They found that radioactive iodine from the fallout
0:33:46 > 0:33:50had been taken up into the thyroid gland,
0:33:50 > 0:33:53and there it had caused tumours.
0:33:55 > 0:33:59It affected children more because the rate of cell division
0:33:59 > 0:34:02is faster in the thyroid when you're young.
0:34:04 > 0:34:07This might have been prevented.
0:34:07 > 0:34:10Iodine tablets contain the stable form of iodine
0:34:10 > 0:34:14which your body takes up in preference to the radioactive form,
0:34:14 > 0:34:17so cancers don't start.
0:34:20 > 0:34:22But, unlike Fukushima,
0:34:22 > 0:34:27in Chernobyl, these tablets weren't immediately made available.
0:34:27 > 0:34:33How many deaths has this resulted in so far?
0:34:33 > 0:34:36TRANSLATION: There were a few cases of deaths.
0:34:36 > 0:34:39The number of deaths for these patients, to be more exact,
0:34:39 > 0:34:44aged 0-18 at the time of the accident, was seven.
0:34:45 > 0:34:50That's an incredible survival rate for this type of thyroid cancer.
0:34:50 > 0:34:53Yes, a high survival rate.
0:34:53 > 0:34:57After five years, we had a survival rate of 99.5%.
0:35:00 > 0:35:02Once the findings of scientists
0:35:02 > 0:35:08from across other contaminated areas of Belarus and Russia were added in,
0:35:08 > 0:35:11they found a total of 15 deaths
0:35:11 > 0:35:15amongst 6,000 cases of thyroid cancer,
0:35:15 > 0:35:18Within a population of some six million.
0:35:23 > 0:35:27People will listen to you, and they will say,
0:35:27 > 0:35:30"Yes, of course, he is in the Ukraine."
0:35:30 > 0:35:37"He has the old Soviet mentality of sticking to a particular line."
0:35:37 > 0:35:40"Why should we believe him?"
0:35:40 > 0:35:42TRANSLATION: It has already been recognised
0:35:42 > 0:35:46by the world's scientific medical community.
0:35:46 > 0:35:50WHO recognised it, the United Nations recognised it.
0:35:50 > 0:35:52These results have been published
0:35:52 > 0:35:55in the most respected scientific journals,
0:35:55 > 0:35:59in particular, in Nature, in Science, and many, many others.
0:36:06 > 0:36:11At a human level, these deaths are, of course, significant,
0:36:11 > 0:36:14as are the cases of cancer.
0:36:14 > 0:36:17But they are lower than almost anyone expected.
0:36:19 > 0:36:22I think a lot of people will be really surprised
0:36:22 > 0:36:25to hear what Professor Tronko had to say.
0:36:25 > 0:36:29I am pretty convinced by this work on thyroid cancer.
0:36:29 > 0:36:35The numbers are very low. But the statistics seem solid.
0:36:35 > 0:36:39The research is highly respected and acknowledged around the world.
0:36:39 > 0:36:44Of course, it remains to be seen whether this number will grow.
0:36:44 > 0:36:50But it's certainly not this figure that's bandied around -
0:36:50 > 0:36:53tens or hundreds of thousands of cases -
0:36:53 > 0:36:57that seems to be purely a myth.
0:37:04 > 0:37:08The full outcome of Chernobyl is not yet known.
0:37:08 > 0:37:12But the data so far is feeding into an ongoing debate
0:37:12 > 0:37:16about the effects of low-level radiation.
0:37:18 > 0:37:23The thing is, radioactivity is all around us.
0:37:23 > 0:37:26It's in the air that we breathe, it comes out from the ground.
0:37:26 > 0:37:29It's inside our bodies.
0:37:29 > 0:37:32The food that we eat is radioactive.
0:37:32 > 0:37:36All living tissue, for instance, contains radioactive carbon 14.
0:37:36 > 0:37:43This banana cake contains potassium 40. As do these brazil nuts.
0:37:43 > 0:37:45So, every time I have food like this,
0:37:45 > 0:37:49I'm increasing the amount of radioactivity within my body.
0:37:49 > 0:37:52There's a constant background radiation
0:37:52 > 0:37:56that does us no harm at all.
0:37:56 > 0:38:00It's when the level of radiation increases above that background
0:38:00 > 0:38:04that the controversy arises.
0:38:04 > 0:38:07The scientific consensus has been that
0:38:07 > 0:38:13any dose of radiation above the background can cause damage.
0:38:13 > 0:38:17And so, the picture would look like this.
0:38:17 > 0:38:21Harm, against dose, gives a straight line.
0:38:21 > 0:38:26But even low-dose levels could be harmful.
0:38:26 > 0:38:27This remains the consensus.
0:38:27 > 0:38:30But there are a number of scientists who believe
0:38:30 > 0:38:35there may be a different theory. It goes like this.
0:38:35 > 0:38:38Low doses may not be harmful at all.
0:38:38 > 0:38:43There's a certain threshold level above which the harm begins to rise.
0:38:43 > 0:38:48It's a quite different way of thinking about radioactivity,
0:38:48 > 0:38:51and its harmful effects.
0:38:53 > 0:38:57This isn't just different, it's highly controversial.
0:38:57 > 0:39:01There's an ongoing debate over the shape of the curve,
0:39:01 > 0:39:07because it's difficult to collect evidence at such low levels.
0:39:07 > 0:39:11And it's possible that there's a small section of the population
0:39:11 > 0:39:16that may be more sensitive than others to low-dose radiation.
0:39:21 > 0:39:24While the scientific debate continues,
0:39:24 > 0:39:29the people of Pripyat must continue to live their lives.
0:39:29 > 0:39:32They've spent more than 25 years
0:39:32 > 0:39:37trying to understand the impact of radiation on their bodies.
0:39:42 > 0:39:45TRANSLATION: What will it do to me?
0:39:45 > 0:39:47I will die. What else can it do to me?
0:39:47 > 0:39:49Illnesses, suffering and death.
0:39:49 > 0:39:51What other result?
0:39:56 > 0:40:01The studies suggest that it's unlikely that most of these people
0:40:01 > 0:40:04will die, or get ill, from the radioactive fall-out.
0:40:04 > 0:40:07But instead, they live in constant fear
0:40:07 > 0:40:10of what the radiation might have done to them.
0:40:13 > 0:40:16Fear and horror. Horror and fear.
0:40:18 > 0:40:21Or sadness and grief.
0:40:21 > 0:40:24SHE SOBS
0:40:32 > 0:40:38It's a large-scale problem, as Dr Marino Gresko knows first-hand.
0:40:38 > 0:40:43She specialises in counselling Chernobyl evacuees.
0:40:43 > 0:40:45But she's also one herself.
0:40:45 > 0:40:48At the time of the accident, she was a nine-year-old,
0:40:48 > 0:40:50attending school here.
0:40:54 > 0:40:58TRANSLATION: As a rule, the most widespread are still
0:40:58 > 0:41:02depressive moods, anxiety symptoms, worry for the future,
0:41:02 > 0:41:07including worry for their own health and their children and grandchildren.
0:41:10 > 0:41:13Suicidal moods and thoughts are generally present among people
0:41:13 > 0:41:16and some have problems of alcohol abuse.
0:41:19 > 0:41:22Doctor Gresko sees these problems herself,
0:41:22 > 0:41:25in large proportions of evacuees.
0:41:26 > 0:41:33TRANSLATION: Out of all people who were evacuated, about 70% suffer from anxiety and depression.
0:41:33 > 0:41:36And about 40% possibly have alcoholism problems.
0:41:42 > 0:41:47Dr Gresko's statistics refer only to her own patients.
0:41:47 > 0:41:51But there's much wider support for this view.
0:41:51 > 0:41:56The UN-backed Chernobyl Forum report has stated that
0:41:56 > 0:41:59the mental-health impact of Chernobyl is the largest public health problem
0:41:59 > 0:42:02unleashed by the accident to date.
0:42:15 > 0:42:20So what does this mean for the people of Fukushima who have had their lives
0:42:20 > 0:42:25turned upside down by the tsunami and then the nuclear evacuation?
0:42:31 > 0:42:35It seems the greatest threat to their health now may be
0:42:35 > 0:42:38fear of radiation, and the stress of evacuation.
0:42:45 > 0:42:51But of course, the events in Japan have a much wider importance.
0:42:52 > 0:42:59We all face choices over the coming years about how we get our energy.
0:42:59 > 0:43:03It's a question that's made all the more urgent by the issue of climate change.
0:43:08 > 0:43:13If we carry on burning fossil fuels - coal, oil and gas - at the rate we're doing,
0:43:13 > 0:43:19then we risk changing our planet's climate, the effects of which could be devastating.
0:43:21 > 0:43:25And, to my mind, this can never be purely a scientific problem.
0:43:25 > 0:43:30It's indisputably tied up with economics and politics.
0:43:31 > 0:43:34You'll have your views, and I'll have mine.
0:43:34 > 0:43:40But it's a debate that needs to be informed by an assessment of the scientific risks.
0:43:45 > 0:43:50The influence of politics and economics on nuclear power is, of course, nothing new.
0:43:50 > 0:43:54And really from the moment scientists first started to understand
0:43:54 > 0:43:57the power bound up inside the atom, it was inevitable that
0:43:57 > 0:44:01politicians would be drawn to this irresistible bounty of energy.
0:44:04 > 0:44:08And I think these politics have had an impact on my science.
0:44:08 > 0:44:10The science of nuclear physics
0:44:10 > 0:44:16and its attempts to find the safest way to unleash the power of the atom.
0:44:28 > 0:44:31The creation of the atomic bomb was one of the most monumental
0:44:31 > 0:44:34scientific projects of the 20th century.
0:44:45 > 0:44:47It brought terrible destruction.
0:44:47 > 0:44:51But it also demonstrated the power of nuclear physics
0:44:51 > 0:44:55and shortened America's war in the Pacific.
0:44:58 > 0:45:00After the Second World War,
0:45:00 > 0:45:06physicists were lionised as heroes, and there was this tremendous faith
0:45:06 > 0:45:10in science to provide solutions and answers to all the world's problems.
0:45:11 > 0:45:16And as for nuclear technology, well, the belief was that it had brought
0:45:16 > 0:45:21an end to the war, and now, it will provide us with electrical power.
0:45:25 > 0:45:31The atomic age was born. A giant of limitless power at man's command.
0:45:31 > 0:45:34But in the new atomic age,
0:45:34 > 0:45:37there were deep connections between the civilian programme
0:45:37 > 0:45:41for nuclear power, and earlier military projects to build the bomb.
0:45:58 > 0:46:03This is Bentwaters Park on the Suffolk coast.
0:46:03 > 0:46:08It used to be a US Air Force base and was at the forefront of the Cold War.
0:46:11 > 0:46:16This bunker, and every one of these, was a store for one thing -
0:46:16 > 0:46:17nuclear weapons.
0:46:20 > 0:46:23Each one of them was packed full of warheads,
0:46:23 > 0:46:27bombs that could have been used against Soviet Russia in the event of a war.
0:46:33 > 0:46:41Plutonium in warheads could come from both military reactors and the earlier civilian reactors.
0:46:45 > 0:46:52And more generally, the bomb programme and the civilian power programme that followed
0:46:52 > 0:46:58shared the same reactor physics, based on uranium.
0:47:04 > 0:47:06But it didn't have to be that way.
0:47:06 > 0:47:11And at the time there were some who thought it shouldn't be that way.
0:47:11 > 0:47:16Scientists continued to experiment with other ways of producing
0:47:16 > 0:47:21nuclear power - not just from uranium - and the story of what happened
0:47:21 > 0:47:25with one of these alternative fuels is a fascinating one.
0:47:26 > 0:47:30It's one of the most overlooked elements in the periodic table.
0:47:30 > 0:47:32Thorium.
0:47:32 > 0:47:37Some scientists have made great claims for its potential -
0:47:37 > 0:47:40it's more efficient, it burns more completely,
0:47:40 > 0:47:43and it's more abundant than uranium -
0:47:43 > 0:47:47but others see it as a difficult element to work with.
0:47:47 > 0:47:50It's harder to trigger and sustain a nuclear reaction.
0:47:50 > 0:47:55Crucially though, thorium reactors don't produce plutonium
0:47:55 > 0:47:57in a form that can be readily used in weapons.
0:47:58 > 0:48:02One extraordinary man was keen to drive through
0:48:02 > 0:48:04thorium as an alternative nuclear fuel.
0:48:04 > 0:48:07His name was Alvin Weinberg.
0:48:07 > 0:48:10Now, strangely, Weinberg was one of the architects of
0:48:10 > 0:48:14the very earliest uranium nuclear power plants in the US,
0:48:14 > 0:48:17but despite his involvement with these reactors,
0:48:17 > 0:48:20Weinberg was keen to find safer alternatives.
0:48:20 > 0:48:27He became convinced that thorium reactors were the way to go.
0:48:29 > 0:48:32As head of a Government nuclear lab from 1955,
0:48:32 > 0:48:36Weinberg pushed forward his suggestion
0:48:36 > 0:48:40for what he thought was a potentially safer way of producing nuclear power.
0:48:40 > 0:48:46This was a moment when the politics were faced with a choice.
0:48:46 > 0:48:49They could either continue with the thorium reactors
0:48:49 > 0:48:52and explore other safer options...
0:48:56 > 0:49:00..or they could stick with the uranium-based reactors they knew and had invested in.
0:49:05 > 0:49:06They chose uranium.
0:49:11 > 0:49:16Weinberg's plans were sidelined and, after 18 years as director
0:49:16 > 0:49:20of a key government nuclear lab, he was forced out.
0:49:25 > 0:49:31I'm not saying that thorium was, in some way, the lost saviour of nuclear power.
0:49:32 > 0:49:37But Weinberg's story was representative of something different -
0:49:37 > 0:49:40the shutting down of scientific options.
0:49:45 > 0:49:50Now, things have changed.
0:49:50 > 0:49:54The Cold War is long over.
0:49:54 > 0:50:00And there's a renewed interest in finding safer ways to approach nuclear power.
0:50:03 > 0:50:06People are exploring new ideas.
0:50:06 > 0:50:11And some are returning to those which were shelved in the 1970s.
0:50:11 > 0:50:16And revisiting the work of scientists such as Alvin Weinberg.
0:50:16 > 0:50:21What Weinberg had planned was a radically different kind of nuclear reactor.
0:50:21 > 0:50:29Not only did he propose using thorium instead of uranium as a fuel, but to use it in liquid form.
0:50:29 > 0:50:33It's quite incredible to think that so many of Weinberg's
0:50:33 > 0:50:37revolutionary ideas can be found in this book that's over 50 years old.
0:50:37 > 0:50:41And it's a real shame that when the US government closed down
0:50:41 > 0:50:46Weinberg's thorium research, they also stopped all work on liquid-fuel reactors.
0:50:56 > 0:51:00It's perhaps too early to judge whether thorium will realise
0:51:00 > 0:51:05its potential and live up to its promise as a nuclear fuel.
0:51:05 > 0:51:10There are many technical and scientific challenges to overcome.
0:51:14 > 0:51:18But the reason it excites me, as a nuclear physicist,
0:51:18 > 0:51:23is because of the intellectual ambition of the work.
0:51:29 > 0:51:33There are already glimmers of what might be achieved if we do experiment.
0:51:36 > 0:51:40I think one of the most exciting prospects to come out of recent research
0:51:40 > 0:51:43is how to deal with nuclear waste.
0:51:43 > 0:51:49Long-term waste remains radioactive for tens of thousands of years.
0:51:49 > 0:51:53So how to deal with it is a very thorny issue.
0:51:53 > 0:51:56At the moment, the only accepted thing to do
0:51:56 > 0:52:01is to bury it, deep underground, in geologically sealed sites.
0:52:01 > 0:52:04But there's an obvious problem with this.
0:52:04 > 0:52:08It simply sits there as a legacy for future generations.
0:52:11 > 0:52:15Here in Grenoble, in the southeast of France, they're working on
0:52:15 > 0:52:22how to transform long-term waste into something which can be disposed of more effectively.
0:52:27 > 0:52:32Doctor Ulli Koester is in charge of researching this process here.
0:52:32 > 0:52:35It's called transmutation.
0:52:37 > 0:52:39We can turn one element into another.
0:52:39 > 0:52:44So we can destroy long-lived radioactive waste by turning it,
0:52:44 > 0:52:46with this transmutation,
0:52:46 > 0:52:49into short-lived isotopes which go away quickly.
0:52:52 > 0:52:55Ultimately, what happens in any nuclear reactor
0:52:55 > 0:53:02is that by splitting atomic nuclei an element is transformed into other different elements.
0:53:02 > 0:53:07And what they do here is rather similar, just accelerated.
0:53:07 > 0:53:13They take heavy elements that are radioactive for tens of thousands of years and split them
0:53:13 > 0:53:18into lighter ones that are radioactive for just tens or hundreds of years.
0:53:21 > 0:53:24Transmutation is an alchemist's dream, where people try to convert
0:53:24 > 0:53:27lead into gold - which is actually possible
0:53:27 > 0:53:30with a strong accelerator - but the gold price has to go a long way
0:53:30 > 0:53:33before it becomes interesting economically.
0:53:36 > 0:53:41To perform this work they need a specialised nuclear reactor.
0:53:45 > 0:53:53They then take a small piece of radioactive material - in this case, americium 241 -
0:53:53 > 0:53:56and load it remotely into the reactor's core.
0:54:08 > 0:54:15Once deep inside, it's bombarded with a high flux of neutrons, triggering fission
0:54:15 > 0:54:22of as many nuclei in the waste as possible, so burning it up more completely.
0:54:22 > 0:54:27So here we have a 50-times higher neutron flux compared to
0:54:27 > 0:54:31a power reactor, which means we can accelerate the process by a factor of 50.
0:54:31 > 0:54:36Instead of waiting for 50 years for something to happen, we can shorten it down to one year.
0:54:39 > 0:54:45And this blue light in the shielding water is a sign that transmutation is happening.
0:54:45 > 0:54:48It's called Cherenkov radiation
0:54:48 > 0:54:53and it's created by the products released as one element is changed to another.
0:54:56 > 0:55:01After 50 days or so in the reactor, the americium, which had a half-life
0:55:01 > 0:55:08of 430 years, has been transformed into completely different elements.
0:55:08 > 0:55:12Each peak represents a fingerprint for an individual isotope.
0:55:12 > 0:55:19If you find this peak we can look it up and we will find it is a decay
0:55:19 > 0:55:22of Krypton 87, which has a much shorter half-life
0:55:22 > 0:55:27of a couple of hours, so it will decay away very quickly.
0:55:27 > 0:55:31It's a process that can be applied to other, more toxic waste products,
0:55:31 > 0:55:35which can be radioactive for thousands of years.
0:55:35 > 0:55:39It's not yet a working solution for our nuclear-waste problems.
0:55:39 > 0:55:45But it shows what might be possible if scientists are able to pursue wider options.
0:55:55 > 0:56:01So, there is an important question that many of us are wrestling with -
0:56:01 > 0:56:05should Fukushima really be the end of the road for nuclear power?
0:56:07 > 0:56:10And, I think, my answer would be no.
0:56:10 > 0:56:12Nothing is perfect.
0:56:12 > 0:56:15There are, of course, consequences when things go wrong,
0:56:15 > 0:56:23when there's an accident. But then, of course, this is true of all power - coal, oil, gas, renewables.
0:56:23 > 0:56:30What's special about nuclear power is our dread of radiation.
0:56:30 > 0:56:33But my hope is, whatever we decide,
0:56:33 > 0:56:38it will be based on a careful assessment of rational science.
0:56:46 > 0:56:50Subtitles by Red Bee Media Ltd
0:56:50 > 0:56:54E-mail subtitling@bbc.co.uk