It was a cloudy, overcast morning when Fujiwara Tadashi entered Reactor Four’s high security level-controlled area. He and his team of eight personnel were experts in the handling of the nuclear fuel rods and their internal transportation within the plant and onto the site’s internal port where the loading and unloading of the fissile material took place.
Today’s procedure was the final part of this ‘fuel rod shuffle’ operation on Reactor Four. There was a defined programme which was run for each of the six reactors at the Fukushima Plant, specifically defining when fuel rods would be removed and/or replaced. This operation was normally undertaken every two years on each unit and with six units at the site, this meant that a replacement operation was carried out on an average cycle of four months. Each time this took place the process was supported by a small army of people, consisting of contractors and company personnel and would take approximately four weeks to complete.
This particular replacement was an unscheduled event, prompted by an issue with the plant’s cooling system. It was determined that there was a fifteen per cent chance this part of the cooling system would fail to maintain the necessary cooling levels for the fuel rods it regulated over their expected lifespan. In the risk-adverse area of nuclear energy, this relatively insignificant system failure prediction was enough of an issue to move the risk category to the status of ‘Very High’, demanding an appropriate response. Consequently, it had been decided to shorten the operational life span of the uranium 235 rods, by removing them as soon as possible.
To enable the safe shutdown of the reactor, it had required a reduced and intensified reactor period around the use of the fuel rods. This amplified interaction would create an extra dimension to the already complex logistical situation.
The intensity of the process would reduce the source neutrons available for uptake by the uranium 235 rods, allowing them to produce an enhanced type of plutonium within its atomic structure. One with less of the more volatile PU-240 element, which does not readily present itself to weapons manufacture due to its high neutron emittance. This makes handling more complicated, and in addition causes it to be unsuitable for use in a nuclear weapon. The molecular deviation having a tendency to create a ‘Fizzle’ in a hydrogen bomb, the equivalent of a ‘Damp Squib’ in the nuclear weapons world.
This meant that the uranium they would be removing would have less than seven per cent of the contaminating PU-240, holding a greater amount of the more desirable plutonium type PU-239. This was classed as weapons-grade material, which would be required to be eventually added to the twenty–plus tons of weapons-grade plutonium Japan had stockpiled since the inception of its nuclear energy programme, at secret locations across the country, thus giving it the potential to create many hundreds of nuclear weapons if it ever felt the need to do so. The capability regarded by the Japanese government as a tacit nuclear deterrent held as a latent threat. As one politician put it, ‘a turn of a screwdriver from possessing viable nuclear weapons…’
Although now designated as weapons-grade material, it would not be handled any differently by Fujiwara’s team to the methods they employed to handle the standard uranium rods. They already operated at the far extremes of safety that the protocols and guidelines of the nuclear industry demanded, and they were experts in this vocation.
The team were now in the ‘final gowning room’ having already removed their civilian clothes and all items of jewellery, in addition to any cosmetics. The group then donned disposable non-shedding underlayers and the captive shoes held on the ‘clean’ side of the low demarcation ‘step-over’ wall as they all crossed into the operational zones, making their way through airlocks to the first layer of controlled-atmosphere clean rooms. The team carried only their personal dosimeters, devices that measured individual radiation exposure. Those who needed prescription spectacles had an extra pair, along with their safety shoes, stored securely in the inner area. As they moved through the facility, they were enveloped in fully enclosed areas with controlled heating, ventilation and air conditioning (HVAC). This advanced HVAC system was designed to cycle the air volume hundreds of times per hour, purifying it by eliminating dust particles through its High-Efficiency Particulate Air (HEPA) filtration system, which captured 99.9 per cent of particles.
En route to the Reactor Room, the crew traversed through zones of cascading negative air pressures. Each zone had an air pressure 15 Pascals lower than the previous one, a strategic design to ensure the dust particles, potential carriers of contamination, were drawn into the building rather than expelled. This meticulous air pressure management was crucial for maintaining a contamination-free environment.
In the final gowning room, they assisted each other to put on their personal protective equipment (PPE) that they would wear during the operation. This consisted of chemically resistant one-piece hooded suits, gloves, steel toe-capped boots and respirators. Fujiwara and two others would also have radios to communicate with the Operations Centre.
The main part of the task involved removing the spent or defective rods and relocating them to the holding tank, where they were kept inert by the controlled liquid environment they rested in. The next section of rods was then extracted and shuffled around into the now vacated silos. The last waltz of this atomic merry-go-round would be the replacement units which had already been placed in the reserve rod-holding tank, which would then be transported by the giant overhead crane into the final vacant tubes.
The crane was equipped with a lifting capacity of 200 metric tonnes, significantly exceeding its maximum anticipated load in the facility by more than double. This was in keeping with the engineering ethos, that every system had redundancy, back-up and over design, principles which were key to maintaining safety at the plant. It was widely believed that this philosophy was true throughout the site. However, unfortunately, that viewpoint, along with several other widely perceived beliefs, would turn out to be tragically flawed.
Today would be the final phase of the change out. All twenty-five of the units would be removed from their holding tank and inserted into a ‘B class containment & transportation flask’. This unit would then be taken, suspended from the crane to the rear of the structure, rolling along on its massive dual rails that ran the full length on each side of the building. After moving beyond the location of two large isolation doors, the unit would be halted, pausing as the large structures were slid into place and locked into position behind the unit, sealing the reactor area off. The HVAC system would then rebalance itself to maintain the required atmospheric conditions in the now reduced space within the reactor area. Around the suspended cask the area was brought to the ambient pressure of the sea-level conditions outside, and only once this recompression was achieved would the hatch door be opened through the floor. It was big enough to accommodate the lowering of the five-metre flask through its orifice onto a specialised transport vehicle parked beneath. Once safely secured, from there it would be transported to the dockside for shipment. Fujiwara was thankful that the final stage of the operation had gone well for him and his highly skilled team. The site manager had already congratulated him on ‘yet another immaculate undertaking’.
The time was now 14.30, they had done well to complete the task so quickly. With the containment flask firmly positioned on the transport vehicle, they drew upwards the giant suspended hook holding the bespoke jig that had been located on the flask, to allow the unit to be orientated from the vertical to the horizontal plain. The mammoth crane was now stored aside and the great trap door in the floor of the building closed on the now mobile flask of fuel rods below.
With a final personal check that everything had been left correctly, Fujiwara accompanied his team back through the defined decontamination route, shedding layers of protection as they went. There were no females in his group, so all the men then entered the male side of the final changing rooms and began to strip off their disposable undergarments before taking a shower. Each shower cubicle only released its outer door to the ‘uncontrolled areas’ after a minimum of ten minutes of showering had been completed under the high-volume water heads.
Fujiwara was halfway through his de-con shower cycle when the first alarms started to sound. At first, he did not recognise the tone of the siren, it took him a few minutes to realise it was the seismic monitoring system that had been activated. A sudden violent shaking of the shower cubicle he was trapped in, confirmed that they were indeed experiencing an earthquake. He hit the emergency release button on the inside of the shower cubicle, undergoing a proper decontamination had now become the least of his worries. He burst out of the shower door at the same time as three of his colleagues who threw themselves out of their own cubicles.
All four were covered from head to foot in a soapy lather and two of them collided together and hit the floor in a slippery naked entanglement. The two fallen men helped each other to their feet, any embarrassment that would have normally been felt at the incident overridden by their growing fear and anxiety.
Everyone had now grabbed a towel and began to furiously rub the detergent from their eyes and faces. The shockwave was still shaking the building as they threw on their workwear. Partially dressed, some without shoes, they ran out into the corridor beyond.
The shaking began to significantly reduce within the few minutes it took them to leave the area. Out in the hallway people were running in all directions, many in a state of panic. A voice over the PA system was telling people to adhere to their emergency exercise status. Everyone had been trained to follow a pre-prescribed drill in the event of an emergency. For most, it was to simply evacuate to their designated congregation area. For others, depending on their skills, roles and responsibilities, it could be more involved. For Fujiwara it was the latter. He gathered the remnants of his team to one side, now augmented by two additional members who joined them after completing their decontamination process alongside the first group that had already showered and cleaned themselves.
Their new responsibility was clear to him. The flask containing twenty-five significantly enriched uranium fuel rods was now outside the safety of the highly reinforced structures they normally resided within. Although he fully appreciated the incredible robustness of the design and construction of the flask, there was a risk that exposing it to the potentially extreme conditions generated by an earthquake may uncover unforeseen vulnerabilities.
He gave his orders. ‘We need to get to the flask, check on its condition and assist in its safe transportation to a reinforced bay within the fuel rod recovery area.’
That particular building was set aside from the reactors, nestled between the two reactor blocks. Reactors One and Two and Three and Four were housed on one side of the site, the third block housing reactors Five and Six on the other side.
‘We cannot leave the unit exposed,’ he said, looking around the small group. ‘It is our duty to protect it, come what may…’
The men in the team began to realise that they were about to embark on a challenging and potentially dangerous task. Though some of its members were clearly extremely frightened, they said nothing, a few then gave a couple of short bows of agreement before following Fujiwara down to the loading bay. This was where they had last seen the flask mounted on top of the transportation vehicle. It took over ten minutes to get themselves through the streams of people, either exiting the building or moving to their standby positions. One of the team members crashed through the emergency fire escape door that led to the outside. They all piled out of the door behind him into the courtyard beyond. The flask cradled on the vehicle was still parked at the back of the courtyard, below the enormous trap door it had been loaded through earlier.
As they began to run towards it another siren began to sound. There was no confusion over what this alarm meant; it sent a sudden jolt of foreboding through all of them – it was the tsunami warning alert!
On reaching the truck Fujiwara discovered that two of his team had disappointingly disappeared. He pulled open the driver’s side door to find the driver still inside the cab. He had both hands firmly clenched around the steering wheel, his knuckles white, shaking quietly in an inanimate state of terror.
‘Where are the rest of your team?’ Fujiwara shouted at the man.
The man turned to him, relief evident on his face at the arrival of a senior member of staff. He undid the chinstrap of his safety helmet, and said, ‘They have all fucked off… the bastards. As soon as the tsunami alert sounded, the whole lot of them did a disappearing act, including the supervisor.’
‘Can’t concern ourselves with that now, we need to drive these rods to the recovery bay, yes?’
He looked at Fujiwara finding comfort in the familiarity of being given a clear order from a senior.
‘Yes, sir,’ he responded. ‘Good man. Now do that chin strap up, you may have use for that hat in a minute.’ He grinned at the driver, who gave him a nervous, sickly smile in return, but did as he was told.
The cab of the vehicle was large with a row of back and front seats, enough for six people in total, the remainder of his team all jumped into the rear.
‘Let’s go!’ he shouted above the wailing sirens, as he got in the front next to the driver. The man started the engine and the powerful diesel motor roared into life; two black plumes exhausted skyward either side of the cab as the heavy truck lurched into motion.
The combined weight of the truck and the flask filled with fuel rods was over forty tonnes. The transporter was not built for speed, it had six axles and twenty-four wheels, with the restricted speed of 20 km/h. It ground its way around Reactor Four, slowly trundling towards units Three, Two and One, through a landscape increasingly devoid of people, most realising the folly of congregating in groups at sea level during a tsunami alert.
Some had tried to find refuge higher up in the buildings, others had gone to the car park and collected their vehicles and were now trying to escape the complex in their cars, others were still on foot, running out of the site as quickly as they could.
It took them almost fifteen minutes to reach the fuel rod bay, only to find its massive steel doors shut fast. The transporter came to stop in front of the doors. Fujiwara leapt from the cab and ran to the control room entrance. The doors were closed and peering through the windows he could see there was no one inside. Access to the building was controlled by a keyed-in code in conjunction with an electronically programmed smart card.
Forty minutes had now passed since they first heard the tsunami warning alarms. He realised that time was running out for them. He heard someone shouting from above. He looked across to reactor building One, to find a group of people that had made their way onto the roof space calling and gesturing towards them. He could not understand what they were saying but from the excitable gesturing and pointing seawards, he had a terrifying understanding of what they were desperately trying to convey to the men on the ground.
He jumped back into the cab. ‘We need to get the fuck out of here right now. Back this bastard up and get us to the main exit,’ he yelled at the now petrified driver.
The driver did as he was told and they were soon moving down the access road towards the main gate.
‘Won’t this heap of shit go any faster?’ called one of his team from the rear of the cab.
‘Restricted,’ called back the driver over his shoulder in response. It took them nearly ten minutes to reach the gate. Fortunately, the robust security gate remained open, positioned adjacent to one side of the main fence. Of the two rising barriers which covered both sides of the road, one had been smashed open and the other was fully raised. Numerous cars lay abandoned around the covered gatehouse security inspection area. As the truck drove through they could see at least one of the guards lying unconscious on the floor. It looked like he had been beaten up by a group of panicking employees trying to escape the facility when he had refused to open the gates.
One of the team wanted to stop and pick him up, but Fujiwara told the driver to keep going. The man was about to challenge this order, when the sudden appearance of water lapping past on either side of them abruptly halted any further discussion on the matter.
There was now a possibility that the truck and its precious cargo could be swept away by the incoming waters. The group’s only chance of saving it, and hopefully themselves, was to drive inland and hopefully outrun the incoming tsunami.