ANP QUARTERLY PROGRESS REPORT tank would be shielded fairly well, and it would be possible for a man to enter <strong>the</strong> inner tank through a manhole at <strong>the</strong> top for inspection or repair work, even after <strong>the</strong> tank had been closed and <strong>the</strong> re- actor had been run at high power. The water capacity of <strong>the</strong> space between <strong>the</strong> tanks, toge<strong>the</strong>r with <strong>the</strong> water in <strong>the</strong> reservoir above <strong>the</strong> inner tank (approximately 10 ft deep), would be of <strong>the</strong> order of 110,000 gal. Boiling of this water would suffice to carry off all <strong>the</strong> heat generated by <strong>the</strong> fission products for about two days without any fresh water being supplied to <strong>the</strong> outer tank. All <strong>the</strong> various wires, pipes, tubes, etc. connected to <strong>the</strong> reactor and its auxiliaries would pass through carefully laid-out junction panels such as <strong>the</strong> one shown in Fig, 2.7. Such a panel might be installed II of <strong>the</strong> tank shown in Fig. 2.6 with a ight gasketed flanged junction. The various <strong>the</strong>rmocouples, power wiring, etc. could be installed on <strong>the</strong> reactor assembly in <strong>the</strong> shopand fitted with Cannon plugs so that <strong>the</strong>y could be plugged into <strong>the</strong> panel in a short period of time after <strong>the</strong> reactor assembly had been lowered into position in <strong>the</strong> test facility. This should minimize <strong>the</strong> amount of assembly work required in <strong>the</strong> field. The layout investigated as <strong>the</strong> fourth proposed installation would involve placing <strong>the</strong> reactor in- side a sort of swimming pool with water-tight <strong>the</strong>rmal insulation surrounding <strong>the</strong> pressure shell, lines, and pumps. The lines could <strong>the</strong>n be brought out <strong>the</strong> top of <strong>the</strong> water tank to <strong>the</strong> instruments and <strong>the</strong> heat dumps. In <strong>the</strong> event of a severe accident that resulted in a meltdown, <strong>the</strong>re would be sufficient heat capacity in <strong>the</strong> water to absorb <strong>the</strong> heat from <strong>the</strong> fission products for some days before a seriously large amount of water would have been boiled out of <strong>the</strong> pool, Such an arrange- ment could be enclosed, of course, in an air-tight building. This might not be necessary, but it seems likely that, in <strong>the</strong> event of an abrupt melt- down type of failure, <strong>the</strong> high heat capacity of <strong>the</strong> region inside <strong>the</strong> <strong>the</strong>rmal insulation might put so much heat into <strong>the</strong> water in a very short period of e that bubbles would boil violently to <strong>the</strong> surface and disperse entrained fission products. After, perhaps, 10 or 15 min, it seems unlikely that such entrainment would prove to be a problem. The unshielded reactor assembly will weigh approximately 10,000 Ib, <strong>the</strong> lead gamma shield approximately 30,000 Ib, and <strong>the</strong> water in <strong>the</strong> shield approximately 34,000 Ib. The first two of 34 <strong>the</strong>se items could be handled conveniently with a 20-ton crane, while <strong>the</strong> borated water could be pumped in after <strong>the</strong> rubber tanks had been installed for <strong>the</strong> water shield. An arrangement such as <strong>the</strong> double-walled tank shown in Fig. 2.6 should prove to be adequate to take care of any accident not involving sabotage or bombing. The same should be true for ei<strong>the</strong>r <strong>the</strong> hemispherical or circular Quonset type of building. Only <strong>the</strong> NRTS installation would, be- cause of <strong>the</strong> remote location, present a not-too- serious hazards problem if effectively sabotaged. To evaluate <strong>the</strong> merits of each of <strong>the</strong> installa- tions considered, an attempt was made to envision as many accidents as possible that might prove to be serious during <strong>the</strong> course of operation of <strong>the</strong> ART. The worst natural accident that could be envisioned would result in a meltdown. The only source of an explosion that has been envisioned would be ei<strong>the</strong>r sabotage or bombing. If <strong>the</strong> volatile fission products are removed during <strong>the</strong> course of operation, <strong>the</strong> major hazard to <strong>the</strong> sur- rounding area would be from <strong>the</strong> fission products that might be dispersed in <strong>the</strong> course of violent boiling or from an explosion. Although in <strong>the</strong> preliminary hazards analysis consideration was given to operational hazards, operational sabotage, fire, earthquake, flood, windstorm, and bombing, <strong>the</strong> controlling considera- tions appeared.to be those associated with a total reactor tragedy. The total reactor tragedy is con- sidered here as being an accident in which all <strong>the</strong> heat that could possibly be released from <strong>the</strong> chemical combination of various materials in <strong>the</strong> reactor and associated system would be released, toge<strong>the</strong>r with <strong>the</strong> heat from <strong>the</strong> fission products accumulated after extended operation at full power and <strong>the</strong> energy released in an extreme nuclear runaway. The principal hazard associated with an ultimate reactor catastrophe is <strong>the</strong> dispersion of <strong>the</strong> fission products that would have accumulated from extended operation at high power. The key data on <strong>the</strong>se parameters are presented in Table 2.2. In examining <strong>the</strong> data on <strong>the</strong> heat that could be released from <strong>the</strong> combustion of various materials in <strong>the</strong> reactor installation, it is immediately evi- dent that if kerosene or ano<strong>the</strong>r hydrocarbon were used in place of water in <strong>the</strong> shield a very large amount of heat could be released, an amount almost one hundred times greater than that from any o<strong>the</strong>r
A" d OIL IN-l OIL IN-2 NUCLEAR I N STRU M E N TAT I ON 0 0 NaK PUMP DRIVE-2 THERMOCOUPLES CONTROL PUMP ROD PERlOD ENDlNG DECEMBER 10, 7954 Na PUMP DRIVE-I DRIVE-2 SHIELD COOLING IN IN SPARE SPARE SPARE SPARE SHIELD COOLING OUT OUT XENON VENTS He SUPPLY EXPANSION TANK , PRESSURE LIQUID LEVEL SPARES 9 OIL OUT- 1 OIL OUT-2 Fig. 2.7. Junction Panel. UNCLASSIFIED <strong>ORNL</strong>-LR-DWG 4502 35