Documenting history: Minutes of the New Piles Committee meetings BY C. GEORGE LAWSON AND In 1944, a committee of physicists, chemists, and CAROLYN KRAUSE engineers, including three Nobel Laureates, met at Y A PRIL 1944, the physicists, the Chicago Metallurgical Laboratory to explore chemists, and engineers responsible B for the design of the reactors at the new designs for power-producing nuclear reactors. Hanford Site, near Richland, Wash., were satisfied that those reactors would operate The New Piles Committee’s meeting minutes and produce sufficient plutonium for the atomic bomb that helped end World War II. describe the proposed new reactor concepts, many They then formed a committee to explore a variety of reactor concepts, including of which evolved into today’s nuclear technology. breeder reactors that could produce both electricity and nuclear fuel. The committee recommended that reactors be used for the production of electricity for naval vessels and as sources of neutrons to breed nuclear fuels and test candidate structural materials for advanced high-temperature reactors, as well as for other purposes. In effect, the committee charted the future paths for the peacetime nuclear power industry, the nu- clear navy, and nuclear energy research. The committee members included three Nobel Prize winners in physics—Enrico Fermi, James Franck, and Eugene Wigner. The other members were Samuel Allison, Charles Cooper, Edward Creutz, Farring- ton Daniels, Thorfin Hogness, Miles Lev- erett, Phil Morrison, Lee Ohlinger, Freder- ick Seitz, Leo Szilard, “Ace” Vernon, William Watson, Alvin Weinberg, Gale Young, and Walter Zinn. The group called Although this photo (date unknown) was not taken at one of the New Piles Committee itself the “New Piles Committee.” (The meetings, it shows four of the committee members, together on a panel (from left): Walter word “pile,” as in a “pile of uranium fuel and graphite moderator,” was replaced by Zinn, Leo Szilard, Eugene Wigner, and Alvin Weinberg. (Photo: ORNL) “reactor” in 1947 when the Atomic Energy were designed. They met for one-and-a-half breeder reactor partly because of the possi- Commission [AEC] took charge of the na- hours almost every other week between bility of the diversion of nuclear material to tion’s nuclear energy and nuclear defense April and July 1944. outlaw groups intent on making atomic programs.) Fortunately, some of the minutes taken bombs. The committee members met at the Uni- at the meetings of the New Piles Commit- On April 26, 1944, according to the min- versity of Chicago Metallurgy Laboratory, tee have been located and are available.1 utes, Fermi envisioned “one large mother where the water-cooled Hanford reactors Ohlinger prepared an excellent set of meet- plant” that would produce not only a mil- ing notes. lion kilowatts of electricity but also pluto- C. George Lawson is a retired nuclear engineer nium “for consumption in a series of from Oak Ridge National Laboratory. Carolyn Breeder reactors smaller plants.” He saw the energy produc- Krause is editor of the Oak Ridge National Lab- Alvin Weinberg, former director of Oak tion by the mother plant as a way to reduce oratory REVIEW, the lab’s research magazine. Ridge National Laboratory (ORNL) and a the cost of plutonium production. The min- Acknowledgments: Copies of the minutes protégé of Eugene Wigner, wrote about the utes say Fermi “viewed the use of this were obtained with the help of Alvin Weinberg, meetings of the New Piles Committee in his power for the heating of cities.” The min- who knew they were still available; ORNL staff book, The First Nuclear Era: The Life and utes also record these words of Fermi: members Marilyn McLaughlin, of the Communi- Times of a Technological Fixer (American “There may be nontechnical objections to cations and Community Outreach Office, and Institute of Physics, 1994, pp. 38Ð41). this arrangement, for example, the shipment Julie Stewart, of the ORNL Central Files Depart- Weinberg noted that during these meetings, of plutonium to the smaller consuming ment; and retired ORNL employee, A. M. “Bud” Fermi was concerned that the public might plants offers the serious hazard of it falling Perry. not accept an energy source such as a into the wrong hands.”

36 NUCLEAR NEWS November 2004 Why was the New Piles Committee so in- electricity for cities. In addition, the com- terials research and isotope production. terested in the breeder? Weinberg explains mittee believed that mobile reactors should A summary of the reactor types consid- it this way: “At the April 28, 1944, meeting be developed for certain naval vessels but ered by the committee is included in the ac- of the New Piles Committee, Phil Morrison were “impractical” for cars and airplanes, companying table (see next page). had reported the known reserves of uranium mainly because they would require too at workable concentration to amount to much shielding. Nuclear energy research only about 20 000 tons. With so little fuel, Today pressurized water reactors and Because the committee’s evaluation of nuclear energy based only on the 0.7 per- boiling water reactors are used throughout available information on known sources of cent of uranium-235 in natural uranium the world in central power stations. Smaller natural uranium and thorium suggested that could hardly amount to much. Morrison PWRs are employed to propel naval vessels, these materials were limited in supply, the also pointed out at this meeting that the such as submarines and aircraft carriers. committee recommended that the emphasis vastly larger amount of residual uranium in Originally, Capt. Hyman Rickover wanted of the nation’s nuclear research programs the granites could be burned with a positive to power the U.S. Navy’s submarines with be placed on U-238-to-Pu-239 converters energy balance—but only if used in a liquid-metalÐcooled reactors being devel- and thorium breeding reactors that produce breeder.” oped by the General Morrison suggested that “more work Electric Company. should be done on the nuclear development But when Rickover In effect, the committee of thorium because of its greater availabil- told Weinberg about ity and also suggested experiments,” pre- the high thermal effi- charted the future paths for sumably to develop a reactor that would ciency of such a re- convert thorium by neutron bombardment actor concept while the peacetime nuclear power to uranium-233 fuel. In subsequent years, he was at ORNL tak- it was determined that the supply of natural ing a reactor course, industry, the nuclear navy, uranium was not nearly as limited as origi- Weinberg persuaded nally projected, so interest declined in him that in a subma- and nuclear energy research. breeders using thorium. rine, reliability, sim- The New Piles Committee identified, plicity, and small evaluated, and compared possible reactor size are more important than thermal effi- U-233 nuclear fuel. The committee was types. Its members evaluated peacetime ciency, and suggested to him that a PWR also interested in learning about the mer- uses for nuclear reactors, their thermody- was the best match for a submarine. Since cury vapor cycle being explored at General namic potential, possible fuel arrange- then, PWRs have been used widely in both Electric for use as a topping plant for the ments, different types of neutron reflectors, submarines and central power stations. high-temperature reactor because liquid and various coolant-and-moderator combi- Unlike the New Piles Committee, the metal at high temperatures was seen as the AEC during the key to highly efficient power production. Eisenhower adminis- The New Piles Committee members un- The New Piles Committee tration was interested derstood that they must receive funds from in pursuing the de- the U.S. Congress to design “a power pro- identified, evaluated, and velopment of “small ducing pile” using plutonium, which at the mobile piles” for air- time was “being deflected into military compared possible reactor planes. And so, the channels.” Although some basic experi- AEC directed ORNL mental work was being performed during types....[and] evaluated to determine whether World War II, actual development work on lightweight shielding some reactors under consideration by the peacetime uses for nuclear and a small reactor committee did not begin until 1948. could be developed Phil Morrison suggested to the commit- reactors. to create a flyable nu- tee members that the nation needed a “re- clear airplane as part search reactor” that would operate at a high of the Aircraft Nu- neutron flux. Such a neutron-generating re- nations. In the unclassified minutes, how- clear Propulsion (ANP) project. Although actor could be used to test samples of ma- ever, no mention was made of radioactive Weinberg and ORNL researchers agreed terials to determine which ones hold up best waste disposal and nuclear reactor safety. with the New Piles Committee that a nuclear when exposed to neutron radiation. Such Some of the applications for nuclear energy aircraft was not feasible, the ANP project— materials would likely be selected for con- suggested by committee members did not later killed by the Kennedy administration— struction of power-producing reactors de- turn out to be practical: They range from lifted materials development programs to a signed to operate for decades. polymerizing hydrocarbons to produce syn- new level. This argument led to the design and con- thetic rubber to propelling vehicles for the struction of the Materials Test Reactor exploration of the South Pole. Reactor types and uses (MTR) in the late 1940s. The MTR and its The committee believed that the Hanford successors were essentially low-pressure Mobile piles and nuclear aircraft plutonium production reactors should be versions of the light-water reactors, which Reviewers of the minutes might find it studied to improve their operation and pro- dominated nuclear power plants for civil- amusing that the committee briefly consid- ductivity. In addition, the committee envi- ian and naval power. ered the use of “medium mobile piles” for sioned a future path for reactors in the According to the minutes, in 1944, “it use in boats and locomotives and “small United States. The members proposed that would appear desirable to press the devel- mobile piles” for use in cars and airplanes. future reactors should be built to (1) pro- opment of better and more efficient designs The committee concluded that research duce power, (2) breed fissile materials (e.g., for the production of isotopes and let the programs should focus on developing uranium-233 or plutonium-239 fuel from power production piles coast along. Even “large stationary piles”—large reactors— nonfissile thorium or uranium-238), and (3) the high flux piles for radiation sources for for central power stations that generate produce high-neutron-flux sources for ma- experimental purposes will probably re-

November 2004 NUCLEAR NEWS 37 NEW PILES COMMITTEE MINUTES

REACTOR TYPES CONSIDERED BY THE NEW PILES COMMITTEE Reactors for Power Production Presenter Power Level Type of Reactor

2 Fermi 1000 kW electric Small, homogeneous D2O-moderated plutonium burner. Wigner6 54 to 280 MW “Pulsating” homogeneous reactor using slurry of enriched material in

D2O and energy from endothermic chemical reactions. Vernon4, 8 Not specified High-temperature, gas-cooled reactor for electrical energy production. Reactors for Isotope Production Presenter Power Level Type of Reactor

Szilard3 250 MW thermal Fast breeder reactor with enriched material using lead-bismuth (or sodium) as coolant. Fermi2 1000 MW thermal Mother plant to produce Pu-239 for use in smaller power plants; might

be (1) Hanford type, or (2) D2O-moderated heterogeneous or homogeneous, or (3) sodium-cooled converter or breeder. Weinberg6 60 MW thermal Water-moderated, enriched for U-238/Pu-239 conversion. 6 Weinberg 100 MW thermal D2O-moderated homogeneous reactor to produce U-233. Wigner9 2750 to 3300 MW “Pulsating” homogeneous slurry reactor to convert U-238 to Pu-239. Young5 Improvement to Hanford reactors by “flux flattening” and “canning” U in one long tube instead of in slugs. Leak detection during operation was also discussed. Wigner, Weinberg, Allison, Fermi, Discussed using long vertical tubes about 1 cm in diameter, cooled by Vernon, Szilard, Young6 water in several of the reactor types, presented possibly using nucleate boiling for heat removal. Because of the high velocity of the coolant, some method for holding the rods firm would be required.6 Several members discussed the desirability of a reactor core made of U dissolved in other (not specified) metals.3, 7 Reactors as a Radiation Source for Materials Research Presenter Power Level Type of Reactor

Morrison10 1000 kW Beryllium (or its oxide) reflected to burn 1 g/day U-235 or Pu-239, moderated with water. quire the use of enriched material and so actors for isotope production, materials test- mated the cost of nuclear energy. this further justifies greater efforts on the ing, and neutron scattering research. The The New Piles Committee believed that piles for production of isotopes.” U.S. Naval Reactors Branch developed its nuclear energy would eventually replace It is clear that the committee’s consider- Sodium-Cooled Fast-Breeder Reactor pro- coal as a primary heat source for production ations are the basis of U.S. government and grams and its own, classified, PWR. of electricity and heat because of the air pol- industry reactor research and development Universities built or bought research reac- lution caused by burning coal. Allison liked programs of the 1950s, 1960s, and 1970s. tors. Manufacturers of commercial power- the idea of using nuclear power “for heat- These included cooperative efforts among generating equipment and metal alloys de- ing entire cities since it would also elimi- the national laboratories, the Naval Reac- veloped their own versions of PWRs and nate the usual smoke pall.” Today, nuclear tors Branch, and three major companies— BWRs. power provides about 20 percent of the General Electric, Westinghouse, and Gen- The New Piles Committee also identified electricity consumed in the United States. eral Atomics. Smaller companies were the need for increased understanding of heat- The New Piles Committee showed great involved in minor roles. The AEC funded transfer mechanisms, particularly in the boil- foresight in identifying both the research ing region, to ensure that would be required to develop a viable that heat is removed nuclear power industry and the variety of safely from fuel- applications for nuclear energy. This fore- It is clear that the committee’s containing tubes. sight is further underscored by the Depart- The New Piles ment of Energy’s new interest in develop- considerations are the basis of Committee may have ing advanced reactors for the production of U.S. government and industry erred in its estimate hydrogen as well as electrical power. of the cost of nuclear reactor research and energy as compared References with coal, oil, and gas 1. ORNL Central Files, 1-10 MUC-LAO Nos. 17, development programs of in the production of 18, 19, 20, 21, 22, 30, 40, 41, and 42, from April 26 electricity. The esti- to July 28, 1944 the 1950s, 1960s, and 1970s. mate for uranium 2. MUC-LAO No. 17, April 26, 1944 was based on the en- 3. MUC-LAO No. 18, April 28, 1944 4. MUC-LAO No. 19, May 5, 1944 ergy costs of pulver- 5. MUC-LAO No. 20, May 10, 1944 the Homogeneous Reactor Program, izing the ore and separating fissile uranium- 6. MUC-LAO No. 21, May 12, 1944 Molten Salt Reactor Program, and Gas 235 from the more abundant uranium-238. 7. MUC-LAO No. 22, May 24, 1944 Cooled Reactor Program; a project to de- Calculating that burning uranium-235 to pro- 8. MUC-LAO No. 30, July 6, 1944 velop a topping cycle using potassium for duce electricity cost only 2 cents per 9. MUC-LAO No. 40, July 11, 1944 space reactors; and a series of research re- megawatt-hour, the committee underesti- 10. MUC-LAO No. 41, July 26, 1944

38 NUCLEAR NEWS November 2004