Get Out Now!

Tales from the Nuclear Age:

 Copyright© 2010 by Charles Glassmire

_________________________________________________________________

Mar. 26, 2010

Get Out Now!

          Our fuel irradiation capsule had been cooking nicely in the General Electric Test Reactor (GETR) for about eight minutes. We were testing NERVA nuclear fuel material to determine its stability under high neutron flux. The only strange event had occurred at about five minutes in, when the Containment Air Monitor (CAM) had detected a large spike of radiation activity in the air we were breathing. Then the radiation alarm had promptly disappeared, and the CAM strip chart was now back to outputting normal background levels. Dave and I had breathed a sigh of relief, but the white overhauled shift supervisor seemed still concerned. He had a worried expression on his face, as he stood beside the CAM, sifting the strip chart over and over in his hands, as if still looking for something – we didn’t know what.

          The second floor of the containment vessel was rather chilly on the midnight shift, even for southern California. It was now almost two a.m. and we were both a little bleary eyed. Dave had laid aside his suitcoat, while we monitored the strip chart recorder, and I recorded capsule temperatures in the log. The cooling water flow rate was steady, pushing water down the long flexible metal hose removing heat from the outside of the capsule. The fuel in the capsule deep inside the reactor core was beginning to fission from the high neutron flux, and the temperatures were climbing nicely inside the fuel pellets and the surrounding graphite fixture. Temperatures were recorded on a small thermocouple read-out we had calibrated back at the Westinghouse Astronuclear Lab in Pittsburgh, and subsequently shipped the chart recorder to Vallecitos along with the test capsules.

          I watched the capsule internal temperatures climb through red heat and now were approaching the white heat we predicted by our earlier calculations (above 2100 degrees C). The calculation was a bit tricky but our method had been reviewed and approved by the GETR safety committee. By now this type of computation was a standard technique in the nuclear industry. Every layer of material surrounding the fuel pellets in the capsule had been mathematically exactly modeled, and the temperature drops from center to outside the capsule were computed by solving a complex differential equation. We knew the internal temperatures to within a few Centigrade degrees, including the temperature rise predicted in the cooling water flow around the outside of the capsule. Things were actually beginning to look routine.

          Suddenly, at about nine and a half minutes, the Containment Air Monitor (CAM) came alive again! This time it was a long steady deafening alarm – and it continued without pause. Two technicians were instantly at the machine. The needle was again off scale. They examined the strip chart and began whispering and nodding to each other. They pulled down cloth face masks covering nose and mouth, as Dave and I watched numbly. The alarm continued to sound an ear piercing Brrrrrrrpp!  More technicians appeared on the floor below. They were standing and looking expectantly up at us on the second floor. Still undecided what to do, I began making another entry in the logbook, noting the time. Was I fiddling while Rome burned?

          Then a large fire siren alarm began to sound from the ceiling of the Containment Vessel above us. It was a deafening wailing siren, warbling up and down clearly indicating there was a dangerous condition in the reactor. The siren sounds added overtop of the CAM alarm; Dave and I were afraid to admit what was happening. We looked at each other helplessly, unsure but still hopeful.  White suited men were appearing from everywhere, running, all in different directions but with some seeming purpose to their movements. The alarms did not stop now, and the CAM indicator was off scale and not coming back.

          Now a Klaxon horn began to blare still louder than the other alarms. “Oooogah – ooogah! I was now hearing secondary beeping alarms coming from the first floor experiments below. I knew the Klaxon was a signal that the reactor was about to SCRAM due to an emergency unsafe condition. More men appeared running and hollering to each other. Some carried high radiation meters and others, low level Geiger Counters. They were looking anxiously at the dials of the high range meters as they ran and all now had covered their noses and mouths with white facemasks.  Bizarrely I was reminded of the World War II submarine movies as the sub was about to emergency dive. Men were sliding down the metal stairways 3 and 4 steps at a hop. Some simply grabbed the metal rails and slid down without touching the stairs until they hit bottom. Others were trying to get up the stairs against the flow coming down.  I remember thinking this is how the world will end. Locked in a steel cage listening to desperate men running to fix it.

          Dave grabbed up his suitcoat and looked at me helplessly. We were visitors without direction, and with a rising sense of terror as the seconds dragged into alarming minutes. Should we pull the capsule? If the Reactor SCRAMMED it would ruin the capsule experiment. Suddenly a white suited figure appeared in front of me. He seemed to be eight feet tall as I looked up into his eyes. His face was tense but the eyes were calming. He gestured to the stairway and simply said:

          “Get out NOW”!  Then he disappeared.

          I needed no further instructions. Dave and I both headed for the stairs to the first floor. The Airlock was located on that floor. It was the only way out. As we pushed down the stairs I heard the reactor control rods slamming into place putting a stop to all fission processes in the core, and bringing the reactor power level down to zero within a few milliseconds. The Emergency Cooling System then kicked in to remove the latent heat from the core, preventing any core meltdown conditions.

          The inside of the Containment Vessel Airlock door was wide open, and the Airlock was rapidly filling with technicians. There was room for several dozen people in the airlock. It occurred to me as I ran up to the big steel door that, if the door was closed early, any personnel inside the containment would be trapped inside, and could receive dangerous exposures. I took up a position holding the big door open while others rushed by me to enter the lock. Suddenly, the same white clad angelic figure appeared beside me, with the same calming eyes. I looked up tentatively. He placed his right hand above me to hold the door, and silently gestured for me to move on into the airlock. I was quite happy to do so. He clearly knew the drill and wasn’t going to trap anybody inside. Finally the great door was closed and dogged down to vacuum seal the chamber. My ears cracked as the air was scrubbed with safe air and equalized to the outside pressure.

          Slowly the heavy outside door of the airlock swung open to allow us to exit, but we were not out of the woods yet. A dozen suited and masked radiological monitor personnel were waiting for us with Geiger Counters. We were not permitted to leave the wooden shed we were herded into until we had been certified clean, and not carrying any radioactive materials into the outside.

          Each person stepped up, spread his feet apart and raised his arms straight out to the sides. A monitor carefully ran a Geiger Counter Probe over every inch of the person, listening for the rapid clicking in the headphones, which indicated Beta or Gamma contamination. When declared clean, a 3 inch white cardboard diamond on a string was threaded around a shirt button, allowing him to exit. Once in a while a person was flagged and told to remove his overhauls and put them into a yellow painted oil drum with the magenta colored radiation flower symbol on the side. Each persons hair and shoe bottoms were given special attention; also the sweaty underarms. Luckily, when my turn came, I passed inspection with flying colors. Due to my special paranoia, I had watched every move I made in the containment, and was careful not to touch anything not needed. I never sat down, but stood the entire time we were in the Containment Vessel.

          Dave was not so lucky. I noticed he was wearing his suitcoat again. It was an expensive suit – he looked like a million in it and he was clearly proud of the way he looked. When the Radsafe monitor got to the seat of his pants he paused, then went back more slowly, running the probe over the back of the pants. Finally he shook his head.

          “I’m sorry – I’m going to have to have those pants. Please step over here and remove them”.

Dave was flabbergasted, then annoyed, then angry.

          ”This is an expensive suit! “ he protested.

          The monitor said they would keep the pants in hot cell storage to see if there was a short half life to the fission products. They might be able to release the pants some time in the future. But in the meanwhile, the technician smiled,

          “We can give you Westinghouse guys a pair of blue General Electric overhauls to wear back to the motel…sorry that’s all we can do…”

          As we drove back to the motel the sun was rising; we tried to remember where Dave had sat or picked up the contamination. Dave was a mixture of anger and acute embarassment as he walked through the motel lobby wearing a pair of blue overhauls displaying a hugh circle logo across the back proudly showing the words “General Electric” in big white letters. The pretty desk clerk behind the counter stared curiously at him but was wise enough to ask no questions…

 (to be continued…)

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