Stressing that the country has ''comprehensive'' simulation capability, Atomic Energy commission chief Dr Anil Kakodkar said Wednesday that the country did not require additional nuclear tests. Dr Kakodkar was joining issue with a small band of ex-nuclear and defence scientists who have recently questioned the success of the thermonuclear device tested on 11 May 1998 at Pokharan.
Baneberry's accidental radioactive plume rises from a shock fissure
The dissenting scientists, all very senior ex-officials and well informed, have issued a warning to the political establishment at New Delhi not to be pressured into signing contentious treaties, such as the CTBT, as the country may need to go in for additional nuclear weapon tests to validate design and technologies. It is their contention that the 'shot' on 11 May 1998 did not yield the desired results, a claim, they say, which is validated by international observations.
This has been hotly contested by other scientists, including Dr Kakodkar, who was himself part of the 11 May 'Buddha Smiles' tests.
"We have enough data. We have comprehensive simulation capability and therefore there is no need for any more tests," Dr Kakodkar said. "We are very confident about the simulation capability."
The recent controversy was ignited by ex-DRDO scientist K Santhanam, who was intimately involved with the tests. He claimed that as far as the thermonuclear device was concerned it was a 'fizzle,' which in nuclear parlance denotes a failure.
"We used the data of 'Baneberry' nuclear tests of US of 18 December1970 to validate our 3-D simulation for earth motion and displacement and this validated tool was used for bench marking," Dr Kakodkar said.
''Scaling up of neutronic calculations can always be done,'' he said, adding that all the observations and calculations were done by scientists from BARC.
Dr Kakodkar said that the measurements, carried out by BARC scientists were done meticulously and that a large number of diverse instrumentations were used for four independent measurements -- seismic, large teleseismic, accurate measurements at Gauribidanur seismic measurement site; radiochemical samples estimation done by different groups; specific evidence of fusion reaction and 3-D simulation of motion of earth and displacement.
Baneberry nuclear event
In March 2009, TIME magazine identified the 1970 Yucca Flat Baneberry Test, where 86 workers were exposed to radiation, as one of the world's worst nuclear disasters.
On 18 December 1970, the 'Baneberry' underground nuclear test (a code name accorded individually to all nuclear tests, much as hurricanes carry names in the US) conducted at the Nevada Test Site (NTS) released radioactivity into the atmosphere. Baneberry had a yield of ten kilotons and the bomb was buried about 900 feet beneath the surface of Yucca Flat.
The energy cracked the soil in unexpected ways, causing a fissure near ground zero and the failure of the shaft and cap. A plume of fire and dust was released three and a half minutes after ignition, raining fallout on workers in different locations within NTS.
The radiation release or venting resulted in a cloud of radioactive dust that reached an altitude of 10,000 feet. Baneberry's accidental radioactive plume was carried in three different directions by the wind.
The radioactive plume released 6.7 million Curies of radioactive material, including 80 kCi of 131I.
After dropping a portion of its load locally, the hot cloud's lighter particles were carried to three altitudes and conveyed by winter storms and the jet stream to be deposited heavily as radionuclide-laden snow in Lassen and Sierra counties in northeast California, and to lesser degrees in southern Idaho, northern Nevada and some eastern sections of Oregon and Washington states.
The three diverging jet stream layers conducted radionuclides across the US to Canada, the Gulf of Mexico and the Atlantic Ocean.
Extensive geophysical investigations, coupled with a series of 1D and 2D computational studies were used to reconstruct the sequence of events that led to the catastrophic failure.
However, the geological profile of the Baneberry site was complex and inherently three-dimensional, which meant that some geological features had to be simplified or ignored in the 2D simulations. To address this issue, a new study was undertaken that encompassed 3D high-fidelity Baneberry simulations based on the most accurate geologic and geophysical data available.
The computational model used included about 40 million zones and the simulation required approximately 40,000 CPU hours to complete, thus making it the largest simulation of its kind.
The simulation helped establish a new capability to perform underground test containment simulations in 3D.
Following the Baneberry venting, new containment procedures were adopted to prevent similar occurrences.
In 1984, Yucca Flats was called "the most irradiated, nuclear-blasted spot on the face of the earth".
