Radiation Alarm

Tales from the Nuclear Age:

 Copyright © 2010 Charles Glassmire


Mar. 14, 2010

 Radiation Alarm

           We were in southern California at the General Electric Test Reactor, irradiating some NERVA rocket fuel. We wanted to see the damage neutrons might create in the nuclear fuel material. We were up on the second floor on the graveyard shift in the big three story high steel containment vessel which housed the GE reactor.

          I was rather amazed at the inside of the containment. It was inches thick steel, and designed to confine any radiation which might be released during the testing. This didn’t happen often, but reactors were designed to resist most possible accidents in the safest possible way. Designers created whole departments whose only job was to investigate possible accidents, computer model what might happen, and design in safeguards to prevent accidental releases to the environment. 

            I looked around the inside of the containment, and realized the entire thing had been made from metal. Stairways, handrails, tables, steel beams at the top of the curved roof, even the sparse furniture were all made from metal. I felt like we were inside some giant kind of factory manufacturing the future of a new age. But it was a safe approach and the easiest to decontaminate in the event some fission products got scattered around and had to be cleaned up.  Dave had taken off his suit coat and rolled up his sleeves (we both wore white shirts and ties in those days), and now he announced we were ready to insert the fuel capsule. The first capsule was about the size of several Coke cans but a little bigger in diameter. A sixty foot metal hose welded to the top delivered cooling water to prevent overheating as the fuel inside generated fission heat.

            We uncoiled the metal hose, and gently inserted the capsule into the Trail Cable tube. The Trail Cable Facility was a long metal tube which coiled down into the reactor core three floors below us. It was used for insertion tests of special materials which were somewhat smaller than the big irradiation experiments which had to sit directly in test ports inside the reactor and “cook” for long periods of time.

          As I entered notations in the test logbook I started the stopwatch and we both noted the time, and I ignored the sexual implications of what we were doing to the insides of this reactor.  The capsule was slipped gently down the long tube to a precise depth where we knew exactly what neutron flux it would be exposed to. The coolant hose was marked off in three inch intervals so we knew exactly where it was positioned below. While being irradiated, the neutrons would travel right through the double stainless steel cans and cause fissions in the enriched Uranium fuel pellets inside. The energy generated would heat the capsule to around 2,300 degrees Centigrade (white heat and more).

            Once the capsule reached position in the core, there was nothing to do but wait.  Dave and I didn’t say much, it was the culmination of nine months of design and assembly work and a lot of money spent back at the Astronuclear Laboratory, and inside we were both quite excited. But we maintained stoic faces during the wait.

            The capsule had been inserted for about five minutes of the forty-five minute run, when suddenly the Containment Air radiation Monitor (CAM) burped with an ear splitting alarm. Brrrrrrrrrrrrrrrp.  It sounded for several seconds and then promptly shut off.  Immediately a white suited technician appeared (the Shift Supervisor) from nowhere and ran over to the machine, and Dave and I were right behind.  It was spilling out a long paper strip chart of the room air radiation level readings. They showed normal background levels up until the prior few seconds. Then suddenly there was a peak in the tracing, and the needle had gone off the top of the chart!  A few inches later in time, the needle had returned down to normal levels, and the CAM chart now sat calmly spewing out continuous readings of normal background levels saying everything was quite OK.  The three of us looked at each other with puzzled concerned faces. Could some experiment deep in the core have emitted a burst of fission products into the second floor air? The CAM had definitely picked up something in the environment. 

            There are strange critters living in and around nuclear reactors.  The radiation levels are constant and ongoing high levels, and eventually the higher forms of life are destroyed.  Rats and mice no longer scavenge at night. The survivors have lower level nervous systems, oblivious to the radiation. Cockroaches live on nicely in the “hot” environment; they run all around the insides of the containment vessel. So they often stray overtop of the radiation sensors and set off alarms, since their body is covered with fission products. It has proven impossible to eliminate them entirely from the environment. So occasionally they drive the operating staff to distraction by setting off detectors in the floors and ceilings of the reactor.  Yes, in the event of a massive nuclear attack, so the myth goes, only the cockroaches would survive. This, of course, isn’t really true even in this worst case scenario, but it makes a nice story. The reality is that many millions would survive an attack – but that’s a different tale.

            Still staring at the chart he held in his hands, the Supervisor told us it wasn’t a concern, things sometimes happened like this, and waved us away. I went back to the log and entered the event, together with the CAM times and readings. It was probably nothing, but I noticed the Supervisor stayed at the CAM, still peering intently at the chart readings as they slowly pumped out of the machine. Something didn’t feel quite right to me, and I felt strangely ill at ease…

(to be continued…)


One Response to “Radiation Alarm”

  1. Larry Hammond Says:

    Amazing reading indeed!!

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