Camp Century
Rickover is the man most responsible for both the success and the failure of nuclear power. Thanks to Rickover, nuclear power became a reality as much as a decade earlier than it otherwise would have. But Rickover (along with Teller) was an originator of the Two Lies. He thought and taught that any sizable release was intolerable. My guess is that this doctrine was more a product of his concern for his program than his concern for humanity. But either way such a release must be prevented. He insisted this could be done if you followed Rickover's system of quality assurance religiously enough, cost be damned. The Intolerable Harm Lie and the Negligible Probability Lie put a crushing burden on nuclear power, which has prevented nuclear from realizing its promethean promise, and will continue to do so until they are renounced.
An instructive exception to Rickover's control of American nuclear effort was the Army's successful small reactor program in the very late 1950's. This included Camp Century. Camp Century was located at 77N in one of the most inhospitable places on the planet, 6000 feet above sea level on the Greenland Ice Cap, 800 miles from the North Pole, Figure 1.
Figure 1. Camp Century Sled Route. The vertical climb was nearly 2000 meters
In January, 1959, the Army signed a 4.5 million dollar contract with the American Locomotive Company (ALCO) for 10 MWt nuclear plant, dubbed PM-2A. ALCO designed, built, and tested the plant in 16 months. The plant comprised 27 blocks. In mid-summer of 1960, the blocks were shipped to Thule, sledded 150 miles east up on to the ice cap, and erected in 78 days. There is a Army film about Camp Century which I find fascinating despite its promotional tone. Table 1 shows the chronology of Camp Century. Contract signing to operation took 22 months.
Figure 2 shows Century's layout, all under ice in tunnels.
Figure 2. Camp Century Ice Tunnels. Railroad test section not labeled.
Figure 3 shows the reactor being moved into its tunnel.
Figure 3. Camp Century Reactor moving into tunnel.
The reactor operated for three years, setting what at the time was the record for the longest continuous run. In the summer of 1964, Camp Century was shut down. The PM-2A was disassembled and returned to the USA.
Camp Century was a test of the feasibility of Project Iceworm, a plan to house hundreds of mid-range missiles in hundreds of miles of tunnels under the ice.1 Parts of Greenland are only 2000 nautical miles from Moscow. The missiles would be moved around randomly making it nearly impossible for them all to be taken out in a first strike. However, Camp Century showed that the flow of the Greenland Ice Cap toward the coasts was much more rapid than anticipated. The ice tunnels distorted and collapsed; they could not be maintained. The Army reluctantly abandoned the overly descriptively named Project Iceworm.
But from a nuclear power perspective, Camp Century showed what is possible when you combine
1) a non-standard nuclear manufacturer accustomed to building large components in a competitive market,
2) a plant built entirely on an assembly line,
3) transported by ship in blocks to site,
4) an erection time measured in weeks,
5) disassembled by reversing the process,
with an attitude that nuclear power is just another way of making electricity with its own benefits and hazards.2
When Camp Century was abandoned, the reactor and its fuel were removed; but just about everything else, including 200 m3 of diesel fuel and reactor coolant water with an initial activity of 1.2 GBq of activity, was left buried in the ice. The ice flow at the site has been tracked by the Danes ever since, most recently by Colgan et al.\cite{colgan-2023}. The ice is moving southwest at about 3.7 meters per year. But this will speed up as the ice gets closer to the shore. Colgan et al estimate it will hit the shore at Melville Bay in about 7000 years, Figure 4.
Figure 4. Camp Century Ice Route to the Sea. Hot colors indicate faster flow.
This has been promoted as a looming radiological disaster. 1.2 GBq is about 1/800th of the activity of a nuclear powered pacemaker. The deal with the Danes required that the site surface be left with no higher than normal background radioactivity. This was checked and signed off on by Danish personnel.
The longest lived isotope in the coolant is our old friend tritium. Tritium emits a weak electron which for all practical purposes is harmless. Tritium has a half-life of 12.3 years. If we conservatively assume all the ``initial" activity was tritium, by the time the Camp Century ice gets to the sea, the tritium will be reduced by more than a factor of 1.0e170. That's 10 followed by 169 zeros.
The Danes also found that the ice depth at the site has been slowly thickening at about 1 cm/year; but with fairly strong decadal fluctuation, Figure 5. On average, the snowfall has more then compensated for any melting or evaporation. This could change in the future; but the Danish Camp Century Monitoring Program is pretty definite:
Our models suggests that the upper horizon of the Camp Century debris field --- observed at a depth of 32 m in 2017 --- will continue to be buried by persistent net accumulation over the next 80 years under all RCP scenarios. The horizon depth will be between 58 and 64 m in 2100, depending on RCP scenario. We estimate a maximum meltwater percolation depth of 1.1m under all RCP scenarios.\cite{colgan-2021}
Figure 5. Ice Thickness at Camp Century, 1995 to 2022, reference \cite{colgan-2023}}
Camp Century left us with a precious gift, Figure 6, a 1390 meter long ice core, all the way down to the ice base.3 This was the product of a multi-year effort to do what never had been done before. It was our first real record of the climate of the last 100,000 years. The single most important data is the ratio of heavy oxygen, Oxygen-18 to normal oxygen, O-16.. The lower this ratio, the colder the planet, since more of the heavy oxygen in the atmosphere condenses and precipitates out as it moves north before it gets to northern Greenland.
Figure 6. Camp Century Core, O18/O16 ratio, Gray is cold, Black is Warm.
In the figure, you can see the 1930's Heat Wave, the Little Ice Age (150 to 500 years ago), the Medieval Warmth (~1000 years ago), the Roman Warmth (~2000 years ago). the Post Glacial Optimum (3000 to 7000 years ago), and the last Ice Age (10,000 to 100,000). It's all there. CO2 measurements showed that atmospheric concentration of CO2 dipped to around 200 ppm about 20,000 years ago, barely above the level needed to support photosynthesis.\cite{neftel-1982}
There's more. The Army actually drilled about 3 meters into the sediment below the ice. Astonishingly, this portion of the core was pretty much forgotten, until it turned up in a freezer in Copenhagen in 2017. The sedimentary record spans pretty much the whole Pleistocene (roughly the last 3 million years). It contains plant material including well preserved twigs which showed that during that period the Camp Century location was ice-free, at least twice.\cite{christ-2021} The core is still producing papers.
From the Army's point of view, Camp Century was a disappointment, since it was the death knell for Project Iceworm. From a broader perspective Camp Century was a success. It showed us how to look into our planet's past in a new way. Potentially even more importantly, Camp Century demonstrated what's possible if you adopt a non-Rickoverian attitude toward nuclear power. Camp Century demonstrates what's possible if you renounce the Two Lies.
This craziness was the product of inter-service rivalry. The Army had been left out of the strategic deterrence business, because it had been limited to intermediate range missiles. Project Iceworm would get the Army back into that game.
The Army's matter of fact, some would say nonchalant, attitude does have a downside. The Army was interested in simple reactors, which could be operated by ordinary soldiers with a little training. This attitude undoubtedly contributed to the 1961 SL-1 criticality, which killed three soldiers.\cite{mahaffey-2014}[p 138-143] What's needed is a middle ground, a system that balances cost and risk to society's overall benefit.
Camp Century also made an important contribution to nuclear power. In the late 1950's, both the Army and Navy were learning about radiation induced embrittlement of reactor pressure vessels, which raised the ductile transition temperature of the steel. The Navy, under Rickover, was preparing to prematurely replace all its submarine reactors. The Army believed this was unnecessary and developed pressure-temperature profiles during startup and shutdown that avoided the brittle zone. After being dismantled, the Camp Century reactor pressure vessel was tested to destruction. The results showed that the Navy's models were grossly conservative and confirmed the Army's plan, which Rickover grudgingly adopted.\cite{bettis-1967}