2142 ADJuly 12, 2008
2142 AD is the year in which Bayo Canyon, New Mexico will be safe for unrestricted use. But today, it has a radioactive contamination problem on account of the TA-10 complex, Los Alamos National Laboratory, that occupied the wooded canyon until cleanup 45 years ago. What was done here was rather interesting:
The Los Alamos National Laboratory […] conducted 254 radioactive lanthanum implosion experiments from September 1944 through March 1962. The purpose of these experiments was to test implosion designs for nuclear weapons. Conventional high explosives surrounding common metals (used as surrogates for plutonium) and a radioactive source, as small as one-eighth inch in diameter and containing up to several thousand curies of radioactive lanthanum, were involved in each experiment detonated. (Dummer, Tascher, Courtright 1996)
In other words, they built and detonated huge, open-air “dirty bombs.”
To their credit, the TA-10 crew selected a short-lived isotope to use for these tests: La-140 has a half-life of only 40 hours. Unfortunately, though, this lanthanum came in a stew of mixed fission products from the Graphite Reactor in Oak Ridge, including long-lived, bone-seeking Sr-90. A radiochemical lab situated at the east end of the Bayo site purified the La-140, dumping the fission-product waste (much of the Sr-90) into lagoons on the canyon floor. Contamination remaining today is mostly associated with this chemical lab and its lagoons. (More information available here, from the DOE’s Office of Legacy Management.)
Back in May I accompanied Taylor Wilson (who has more photos on his website) and his father on a little radioactive scavenger hunt in Bayo Canyon. Access is via the dirt road (“Pueblo Canyon Road”) leading to the Los Alamos Sewage Treatment Plant. (Caution visitors…this road is gated and may be closed. Enter at your own risk!) On this day we were armed only with scintillation detectors, unfortunately a poor choice for hunting the pure beta-emitting Sr-90 that constitutes most of the remnant contamination. The area around the former radiochemical building (TA-10-1) site is well-marked though, with a combination of chain-link fence, roped-off areas, and little markers as shown in the top photo. We did detect a few above-background areas with the scintillometers, but nothing to get too excited about. Next time, I’ll take a pancake GM detector!
Bayo Canyon is a great place for a quiet day hike and picnic near Los Alamos, with some interesting history for the nuclear tourist to boot. Where else on earth can you picnic on dirty-bombed ground?