An Ode to HWCTR

HWCTR is an acronym that might be familiar to you, but if not, maybe the name “Hector” will ring a few bells. The Heavy Water Components Test Reactor, commonly referred to as Hector, began its life has the brainchild of an Atomic Energy Commission (AEC) that was determined to capitalize on the possibility of a heavy-water reactor. HWCTRs’ life did not continue on the path that the AEC had originally envisioned, but thanks to the meticulous documentation efforts of DuPont and SRP, we can still observe the incredible work that went into its creation.

Heavy water (D20) was the source of much debate in the early nuclear age, particularly regarding its efficacy as a reactor moderator and its economic viability when compared to light water. Concrete plans for HWCTR were proposed by the AEC in 1956, then being referred to as the Power Components Reactor (PCR). However, these plans quickly faced a number of complications, not the least of which being that the proposed test reactor was shown to be much too small to be economical in preliminary studies. This led to the reactors’ ideal electrical output being increased from 100 MW to 400 MW.

By August of 1956, the AEC already had a much-reduced role in the test reactor project and turned the keys over to DuPont, who began working on a second proposal with their internal Atomic Energy Division and Engineering Department. Presented to the Savannah River Operations Office (SROO) in January 1957, DuPont’s proposal was anything but small. Their research suggested that to compete economically, they would need to build a reactor capable of creating up to 460 MW of electricity, with construction budget of $15 million. While SROO was more than willing to comply, going as far as to allocate $16.5 million for PCR, the AEC decided that the allotted amount was far too large. Instead, DuPont would work with a $6.4-million facility budget, with an additional $800,000 for the transferring of heavy water.

After several more revisions to the proposal, the project was approved by the AEC in November 1958. Now known as HWCTR, the proposed facility was projected to output 61 MW and would be 70 feet in diameter and 125 feet high, with almost 60 feet of the structure below ground. Construction began in 1959 in what was then called 700-U area, now known as B-Area. Once again, HWCTR found no easy path forward, as building delays led to the facility not being completed until October of 1961. Once operations began in 1962, maximum power was measured to be about 70 MW, and a computer program created by DuPont was used to help measure the range of heavy water and reactor activity.

Unfortunately, the process of planning and constructing HWCTR lasted longer than HWCTR itself. By December of 1964, the reactor was shut down, and the facility was placed on a permanent “six-month” standby. However, HWCTR’s two years of operation were by no means wasted time and effort! During its operation, the reactor demonstrated good neutron economy with lower fuel costs. Researchers were also able to draw conclusions regarding the best fuel, coolants, and power levels for an ideal heavy water reactor. While this research has proved invaluable for modern heavy water reactors, by 1964 the clear preference for civilian reactors was light water based. Not only could these facilities be built and operated at a lower cost, but the cost of heavy water itself was still an expense that couldn’t be readily overcome. During HWCTR’s heyday it operated at a nominal reactor power of 50 MW and tested 36 different fuel assemblies. By the end, it generated a total of 13,882 MW and cost a total of $8.9 million. 

“Here our epilogue ends, with thoughts of the friends
Who remain or are long departed.
And we think of their deeds, and the words of the Swede,
And the mighty reactor we started.” 
– from Epilogue I, by S.H. Hale and J.C. Hobbs