I
C. RICHARD BERGEN and JULIUS CHUPAK Nuclear Power Engineering Department, Alco Products, Inc., Schenectady, N. Y.
Corrosion and Activity Build-Up in a Power Reactor O n inner surfaces of the primary system,the film of corrosion products, which the coolant constantly deposits and picks up again, gets thicker a t a decreasing rate, but its radioactivity builds up a t an increasing rate. To prevent this radioactivity build-up, inhibiting redeposition of suspended material from the coolant seems more promising than increasing purification rate.
ion exchange. There are two columns in the system, but one is held in reserve. Finally, the stream passes through a sintered stainless steel filter, which removes resin fines, and then is pumped as needed to the primary system after a decay period in the make-up tank.
Sampling Procedures Type
304 stainless steel coupons,
STEAM GENERATOR
THE
i
SM-1 (Army Package Power Reactor) at Fort Belvoir, Va., was designed, constructed, and operated during the past three years by Alco Products, Inc., under contract with the U. S. Atomic Energy Commission. The reactor has a 10-Mw. heat output, a 2-Mw. electrical capability, and a load factor which has averaged about 62 to 70’%. It is a prototype, and the research tasks and operator-training programs which have been carried out have resulted in an erratic “yo-yo” operation from day to day. This erratic operation is probably not representative of future reactors of this type, and has some effect on coolant chemistry. Except for minor amounts of other materials such as Stellite and Type 17-4 stainless steel, components in contact with the primary coolant are Type 304 stainless steel. The primary coolant is held under a pressure of 1200 p.s.i., and at a temperature of 450’ F. by heat from the core. The coolant, high purity water of neutral pH, is circulated at 4000 gallons per minute. It gives up heat in the steam generator and is returned to the heat source through the cold leg at 430’ F. Water purity is maintained by diverting a 0.6 gallon-per-minute side stream to a purification system. The stream passes first through a cooler which reduces its temperature to less than 120’ F., and then to a niotor-driven throttling valve which reduces pressure to less than 100 p.s.i. Soluble and insoluble impurities are removed by mixed-bed
inserted in the purification stream just ahead of the cooler, were removed periodically to determine corrosion rate and crud film and activity build-up. The crud film from these coupons was assayed for the radionuclides, chromium51, manganese-54, cobalt-58, iron-59, and cobalt-GO. Also, crud samples were collected periodically by filtering the coolant. A fritted stainless steel filter was used upstream of the demineralizer
PRESSURIZER
PUMP PRESSURE VESSEL
E RS
FILTER MAKE-UP TAN K Water purity in the primary system is maintained by diverting a side stream to a purification system VOL. 52, NO. 8
AUGUST 1960
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Table I.
Determination
Range of Chemistry for Two Years’ Operation Upstream Downstream Make-Up Demineralizer Specifications Demineralizer Tank 0.5 p.p.m. max.
