b'P ROVING THE P RINCIPLEgamma radiation from the reactor was inferred cross section was used to The boat had be dry docked whilenitrogen-16, which was generated in the design the shielding. The facilities at welders cut open the skin of the boatreactor cooling water when a stray neu- the NRTS were essential to solving thisand removed the reactor the same waytron struck an atom of oxygen-16. What key question bearing on the radiation a surgeon might remove a bad appen-they didnt know was how likely it was safety of the Navy crew. dix. The procedure would tie up the11for any given number of nitrogen atoms boat for up to two years, hardly theto capture neutrons and therefore how Another issue for the Navy was the place for a weapon system during warbig a problem nitrogen-16 would be. long life of the reactor and its fuel. or an international crisis.Dr. John Taylor, responsible for the Changing fuel in the cramped spaces ofNautilusshielding studies, recalled: a submarine was extremely inconve- The Navys Westinghouse team sentnient, not to mention hazardous. sample capsules to the MTR for irradia-Because the half-life of nitrogen-16 is Replacing the entire core was worse. tion for the requisite number of weeksonly 7.35 seconds, the capture cross- or months, whatever would duplicatesection [probability of capture] could the capsuleslifetime radiation in anot be measured by the normal acceler - ship. The team sent fuel alloys, controlator methods. Without that information rod materials, and structural metals.there was no way to design the major The work was highly classified; MTRcomponents of the shielding for the workers sometimes did not know whatsubmarine. Thus, a closed loop was was inside the test capsules.installed in the MTR to circulate waterthrough the MTR neutron flux so as to Westinghouse scientists took the cap-be able to measure the nitrogen-16 sules back to their own labs, dismantledactivity generated in the water. The them, and studied them in minutedetailweigh, X-ray, measure, count.INEEL 64-2056 Little by little, they learned whichmaterials would hold up and whichwould not. The scientific habits of mak-ing predictions, observing closely, andkeeping detailed records were the sameas those so recently practiced by theBureau of Ordnance. Every experimentat the MTRand everywhere else atthe NRTSbegan with the sponsorsprediction and ended with some incre-ment to the worlds store of knowledge,however large or small.Above. A straddle carrier transported spent fuelelements from the MTR to the Chem Plant. Left.Fuel elements cool in the MTR canal. As a sideexperiment, a can of food rotates in a special rig sothat contents get equal exposure to gammaradiation.INEEL 55-9737 0'