Nuclear disaster site as a tourist attraction?
This is a two part posting. The first gives history to those of you who do not know what happened, or for those of you who would like to know more of what happened. The second part is what prompted me to do this posting.
25 April, 1986 : Chornobyl (Unkranian Spelling)
Border of Russia, Belarus and Ukraine
A routine shutdown for maintenance was occurring. It was determined that it would be a prime opportunity as a test, to determine how long turbines would spin, and supply power to the main circulating pumps following a loss of main electrical power supply.
The test had been run the previous year, but due to things found and fixed during that test, they were trying it again.
The planned programme called for shutting off the reactor’s emergency core cooling system (ECCS), which provides water for cooling the core in an emergency. Although subsequent events were not greatly affected by this, the exclusion of this system for the whole duration of the test reflected a lax attitude towards the implementation of safety procedures.
As the shutdown proceeded, the reactor was operating at about half power when the electrical load dispatcher refused to allow further shutdown, as the power was needed for the grid. In accordance with the planned test programme, about an hour later the ECCS was switched off while the reactor continued to operate at half power. It was not until about 23:00 on 25 April that the grid controller agreed to a further reduction in power.
For this test, the reactor should have been stabilised at about 700-1000 MWt prior to shutdown, but possibly due to operational error the power fell to about 30 MWtb at 00:28 on 26 April. Efforts to increase the power to the level originally planned for the test were frustrated by a combination of xenon poisoningc, reduced coolant void and graphite cooldown. Many of the control rods were withdrawn to compensate for these effects, resulting in a violation of the minimum operating reactivity margind (ORM, see Positive void coefficient section in the information page on RBMK Reactors) by 01:00 – although the operators may not have known this. At 01:03, the reactor was stabilised at about 200 MWt and it was decided that the test would be carried out at this power level.
The following is a timeline taken of the incident. It was made available at The world Nuclear Association and can be found here:
Please note, The sequence of events which follows has been compiled following a review of a large number of reports and it represents what is considered the most likely sequence of events, but there remain some uncertainties.
- 01:06 The scheduled shutdown of the reactor started. Gradual lowering of the power level began.
- 03:47 Lowering of reactor power halted at 1600 MW(thermal).
- 14:00 The emergency core cooling system (ECCS) was isolated (part of the test procedure) to prevent it from interrupting the test later. The fact that the ECCS was isolated did not contribute to the accident; however, had it been available it might have reduced the impact slightly. The power was due to be lowered further; however, the controller of the electricity grid in Kiev requested the reactor operator to keep supplying electricity to enable demand to be met. Consequently, the reactor power level was maintained at 1600 MWt and the experiment was delayed. Without this delay, the test would have been conducted during the day shift.
- 23:10 Power reduction recommenced.
- 24:00 Shift change.
- 00:05 Power level had been decreased to 720 MWt and continued to be reduced. Although INSAG-1 stated that operation below 700 MWt was forbidden, sustained operation of the reactor below this level was not proscribed.
- 00:28 With the power level at about 500 MWt, control was transferred from the local to the automatic regulating system. The operator might have failed to give the ‘hold power at required level’ signal or the regulating system failed to respond to this signal. This led to an unexpected fall in power, which rapidly dropped to 30 MWt.
- 00:43:27 Turbogenerator trip signal blocked in accordance with operational and test procedures. INSAG-1 incorrectly reported this event occurring at 01:23:04 and stated: “This trip would have saved the reactor.” However, it is more likely that disabling this trip only delayed the onset of the accident by 39 seconds.
- 01:00 The reactor power had risen to 200 MWt and stabilised. Although the operators may not have known it, the required operating reactivity margin (ORM) of 15 rods had been violated. The decision was made to carry out the turbogenerator rundown tests at a power level of about 200 MWt.
- 01:03 A standby main circulation pump was switched into the left hand cooling circuit in order to increase the water flow to the core (part of the test procedure).
- 01:07 An additional cooling pump was switched into the right hand cooling circuit (part of the test procedure). Operation of additional pumps removed heat from the core more quickly leading to decreased reactivity, necessitating further absorber rod removal to prevent power levels falling. The pumps delivered excessive flow to the point where they exceeded their allowed limits. Increased core flow led to problems with the level in the steam drum.
- 01:19 (approx.) The steam drum level was still near the emergency level. To compensate, the operator increased feedwater flow. This raised the drum level, but further reduced reactivity to the system. The automatic control rods went up to the upper tie plate to compensate but further withdrawal of manual rods was required to maintain the reactivity balance. System pressure began to fall and, to stabilise pressure, the steam turbine bypass valve was shut off. Since the operators were having trouble with the pressure and level control, they deactivated the automatic trip systems to the steam drum around this time.
- 01:22:30 Calculations performed after the accident found that the ORM at this point proved to be equal to eight control rods. Operating policy required that a minimum ORM of 15 control rods be inserted in the reactor at all times.
- 01:23 (approx.) Reactor parameters stabilised. The unit shift supervisors considered that preparations for the tests had been completed and, having switched on the oscilloscope, gave the order to close the emergency stop valves.
April 26: the test
- 01:23:04 Turbine feed valves closed to start turbine coasting. This was the beginning of the actual test. According to Annex I of INSAG-7, for the following approximately 30 seconds of rundown of the four coolant pumps, “the parameters of the unit were controlled, remained within the limits expected for the operating conditions concerned, and did not require any intervention on the part of the personnel.”
- 01:23:40 The emergency button (AZ-5) was pressed by the operator. Control rods started to enter the core, increasing the reactivity at the bottom of the core.
- 01:23:43 Power excursion rate emergency protection system signals on; power exceeded 530 MWt.
- 01:23:46 Disconnection of the first pair of main circulating pumps (MCPs) being ‘run down’, followed immediately by disconnection of the second pair.
- 01:23:47 Sharp reduction in the flow rates of the MCPs not involved in the rundown test and unreliable readings in the MCPs involved in the test; sharp increase of pressure in the steam separator drums; sharp increase in the water level in the steam separator drums.
- 01:23:48 Restoration of flow rates of MCPs not involved in the rundown test to values close to the initial ones; restoration of flow rates to 15% below the initial rate for the MCPs on the left side which were being run down; restoration of flow rates to 10% below the initial rate for one of the other MCPs involved in the test and unreliable readings for the other one; further increase of pressure in the steam separator drums and of water level in the steam separator drums; triggering of fast acting systems for dumping of steam to condensers.
- 01:23:49 Emergency protection signal ‘Pressure increase in reactor space (rupture of a fuel channel)’; ‘No voltage – 48 V’ signal (no power supply to the servodrive mechanisms of the EPS); ‘Failure of the actuators of automatic power controllers Nos 1 and 2’ signals.
- 01:24 From a note in the chief reactor control engineer’s operating log: “01:24: Severe shocks; the RCPS rods stopped moving before they reached the lower limit stop switches; power switch of clutch mechanisms is off.”
As a direct result of the accident, around 50 people died. It is most likely unable to be determined how many people have died or will die as a result of the after effects of the accident.
This was certainly the worst nuclear accident in our history however; it has been reported that it has been an unofficial tourist attraction for some time. The Ukraine government has allowed people to start re-populating the area and they have decided to open the area up as an official tourist attraction.
Where tourists are allowed to go, how long they may stay, and what they eat will be carefully controlled, government officials say, so the radiation risks are “negligible.”
“They will be properly channeled at all times,” said Vadim Chumak at the Research Center for Radiation Medicine of Ukraine.
Scientists researching the effects of Chernobyl at the U.S. National Cancer Institute declined comment, deferring to Chumak, but an unaffiliated biologist pointed out that many other adventurous vacations (think a steep mountain climb) are not risk-free, either.
I’m sure they are thinking that this will help decrease the possible unwanted visitors to areas that are to be off limits, but there are those that will still try and get where they’re not supposed to be.
I don’t know how I would feel though about someone coming to ogle over the site of a tragic accident unless they were there to observe, study, and try and find out ways to help those that are affected by a radiological accident such as this.
My heart goes out to all those who have suffered because of this accident and the families and friends of those that were lost. I just hope that this ‘tourist attraction’ thing turns out to be a good think for both the residents, the families and the Ukraine itself. Only time will tell.
On a lighter, sick, twisted side, I could see a theme park built up there and a gift shop. They could pull in some movie stars and get someone from the movies Nuke Em High, Damnation Alley, Dr. Strangelove, and The Toxic Avenger to be the characters walking around.
They could have rides such as:
Maybe some kind of toxic tunnel of love or something.
They could also have a gift shop.
It could sell kids (or adult) size radiation suit play sets, etc.
Something tells me though that not only what I just said is in bad taste, but having it actually take place would cause riots.
Anywho, there you have it. A nuclear disaster turned tourist attraction.