Kenneth David Nichols CBE (13 November 1907 – 21 February 2000) was an officer in the United States Army, and a civil engineer who worked on the secret Manhattan Project, which developed the atomic bomb during World War II.

On this project, Nichols worked with DuPont and Stone & Webster as major contractors, and dealt with Leslie Groves, now the colonel in charge of military construction.

On 30 June Nichols and Marshall set out for Tennessee, where they met with officials of the Tennessee Valley Authority and looked over prospective sites in the foothills of the Cumberland Mountains that had been identified (by scouts from the Office of Scientific Research and Development) as possessing the desirable attributes of abundant electric power, water and transportation with sparse population.

A site at Oak Ridge, Tennessee was chosen, but Marshall delayed purchase while he awaited scientific results that justified a full-scale plant.

He arranged with the State Department for export controls to be placed on uranium oxide and negotiated with Edgar Sengier for the purchase of 1,200 tons of ore from the Belgian Congo that was being stored in a warehouse on Staten Island.

[10] Nichols met with Undersecretary of the Treasury Daniel W. Bell and arranged for the transfer of 14,700 tons of silver from the West Point Depository for use in the Y-12 National Security Complex in place of copper, which was in desperately short supply in wartime.

[14] Groves soon decided to establish his project headquarters on the fifth floor of the New War Department Building in Washington, D.C., where Marshall had maintained a liaison office.

[18] For his wartime work on the Manhattan Project, Nichols was awarded the Distinguished Service Medal by the United States Secretary of War, Robert P.

Asked to spend more time on weapons production and storage, Nichols established a new underground assembly plant at the Mound Laboratories in Miamisburg, Ohio, and recommended that Sandia Base be transferred from the United States Army Air Corps to the Manhattan District.

[19] In June 1946, Nichols went to Bikini Atoll to represent the Manhattan Project at Operation Crossroads, a series of nuclear weapons tests conducted to investigate their effects on warships.

[24] In December 1946, Nichols recommended the closing down of the alpha tracks of the Y-12 plant, thereby cutting the Tennessee Eastman payroll from 8,600 to 1,500 and saving $2 million a month.

[26] AEC Chairman David E. Lilienthal objected, but Nichols pointed out that the proposal had been included in their briefing when the commission visited Oak Ridge in November.

[28] He helped Captain Hyman G. Rickover train a team of naval engineers at Oak Ridge in nuclear propulsion.

With a retirement age of 65 he looked forward to almost 26 years of "pleasant and comfortable" academic life with a house on the Hudson, and to Jackie "a wonderful place to raise Jan and David".

Although his rank entitled him to quarters at Fort Myer, Virginia, the Chief of Staff of the United States Army, General Omar Bradley advised him not to ask for them as there had been criticism from some senior colonels.

[32] For a time there was talk of calling off the Operation Sandstone nuclear weapons tests, but Nichols successfully argued for their continuation.

[36] In this capacity he initiated the AEC Personnel Security Board hearing on the loyalty and trustworthiness of atomic scientist J. Robert Oppenheimer.

In a harshly worded memorandum to the AEC on 12 June 1954, subsequent to the hearing, Nichols recommended that Oppenheimer's security clearance not be reinstated.

In five "security findings", Nichols said that Oppenheimer was "a Communist in every sense except that he did not carry a party card," and that he "is not reliable or trustworthy.

[38] A second scandal was the Dixon-Yates contract, a political controversy that became a major issue in the 1954 elections, resulting in Nichols appearing before a United States Senate subcommittee.

His clients included Alcoa, Gulf Oil, Westinghouse Electric Corporation and the Yankee Rowe Nuclear Power Station.

He was critical of over-regulation and protracted hearings, which meant that by the 1980s similar boiling-water or pressurized-water plants took almost twice as long to build in the United States as in France, Japan, Taiwan or South Korea.