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Saturday, September 24, 2011

APR Atomic Journal - Elk River part 2

In the first installment of this series, we discussed the origins of the Elk River Power Reactor (as it was called at the time) using as source material many original documents and sources. We conclude the story of the Elk River plant as shown in these documents with this installment of the APR Atomic Journal.

Construction underway

Our previous installment on Elk River ended with the announcement (in September, 1958) that Chicago Bridge and Iron had been selected to construct the containment for the Elk River plant. Other long term contracts (known as "long lead time" contracts) began to be awarded at the same time; Sargent and Lundy, Inc. were brought in as architect-engineers and the Maxon Co. of Dayton, Ohio was hired as the construction contractor. In the first quarter of 1958, the estimated total cost to the AEC for the Elk River project was almost $11.5 million, with the Rural Cooperative Power Association providing facilities costing about $1.75 million. The AEC cost included a fixed ceiling contract with ACF Industries to develop and construct the reactor plant, train operators and perform testing. At that time the plant was expected to be completed by October of 1960 (AIF Forum Memo magazine, May 1958.)

Groundbreaking for the new plant (actually, for the reactor plant portion at the site) took place on August 4th, 1958. Construction of the containment began in October, 1958. As noted before, the nuclear portion of the plant was entirely owned by the AEC; interestingly the AEC advance budgeting as announced in mid-1959 did include an earmark for $100,000 for operating funds for the year 1960, as opposed to construction funds, as it was considered at that time that the plant would be operational sometime in that year.

Vendor upheaval

In the middle of 1959, a major change occurred to the project; ACF Industries decided to exit the reactor business completely. In this transition for ACF it was decided to sell the nuclear products operations, but not the ERCO operations (the nuclear products and ERCO divisions had been merged together by ACF Industries on April 1, 1957.) ACF sold its entire nuclear business to Allis-Chalmers Manufacturing Company, including not only the Elk River project but the various test and training reactors it had under construction. This was the second of two rapid and somewhat major transactions in the nuclear energy field; also in 1959, General Nuclear Engineering Corporation was bought by and merged into Combustion Engineering, Inc.

Allis-Chalmers at this time had one power plant contract, which was for a boiling water reactor for Northern States which would become known as the Pathfinder Atomic Plant. Allis-Chalmers immediately integrated the ACF operations into its own, and in fact the 1960 Allis-Chalmers annual report supplement makes absolutely no mention of work underway as "ex-ACF" or any such thing; it is all A-C so far as this document is concerned.

Below we see our first photo for this installment. This is a previously unduplicated UPI Telephoto dated February, 1960.

This photo shows the arrival at the Elk River site on February 11, 1960 of the reactor pressure vessel on what appears to be a standard 40-foot railroad flat car. This pressure vessel was fabricated by Pacific Coast Engineering Company, of Alameda, California. The control rods on this reactor plant are bottom entry; thus, the lower end of the pressure vessel is at left. According to the caption on the UPI Photo (in the APRA collection) the vessel weighed 72 tons, and was to be placed in a minimum of 8 feet 3 inches of concrete shielding. The caption also states an expected date of completion of November, 1960.

Elk River plant details

Let's now briefly take a look at the design of the reactor plant in some closer detail. Below is an illustration from "Boiling Water Reactors," Andrew W. Kramer / Addison-Wesley 1958 as published as part of the 1958 Geneva Conference set in the APRA collection.

This illustration shows the reactor vessel in good detail. The reactor plant at Elk River was conceived originally as being convertible; although it was completed and operated only as an indirect-cycle BWR plant, it was convertible to forced circulation with the use of installed, but capped and welded, nozzles as indicated in the drawing above. None of the recirculation equipment was ever ordered.

The Elk River plant was rated at 22MWe; the thermal output of the reactor itself was rated 58.2 MWt, while the coal-fired superheater was credited with 14.8 MWt for a total thermal power of 78 MW.

In the photo showing the arrival of the reactor vessel, the nearly complete containment is visible behind it; below, also from "Boiling Water Reactors," is another illustration showing equipment layout inside the containment with the reactor plant complete.

In this view we can see the equipment labeled "evaporator," which in any other plant would be called a steam generator. This plant's use of the indirect cycle was intended to take advantage of the fact that the steam would carry no radioactivity into the turbine building (the turbine generator that Allis-Chalmers was designing for Northern States was very heavily shielded; that for Elk River was not.)

The control system for the plant used, as its primary input, the pressure of steam exiting the superheater. Variations in this pressure caused immediate but fine motion of the nine control rods, made of boron-steel.

This reactor was one of two early reactors (the other being Indian Point 1) which used uranium and thorium fuel to explore the thorium fuel cycle. The initial fuel loading for the plant was 195 kg of uranium and 4200 kg of thorium dioxide, all in pellets inside stainless steel tubes.

Construction, testing, delays

As has been the case with most nuclear plants, unexpected delays began to push the actual startup date back, then pushed it far off. Although the plant itself was practically completed by fall of 1961, almost a year off the initial target, problems with the reactor itself - fuel element defects and problems with the stainless steel pressure vessel internal cladding - pushed anticipated startup as perceived in late 1961 to probably late 1962. (Atomic Energy Deskbook, Hogerton, 1963.)

Above is a post card view (APRA collection) showing the Elk River plant in a state of partial completion in 1959. The reactor plant containment is visible on the right, the turbine building on the left. The interposed superheater section is not yet constructed.

Above is a photo taken from a very similar angle, which was included in the 1960 Allis-Chalmers annual report. This report states that construction at this time was virtually complete, and the final appearance of the plant is now established - except for the fact that, for whatever reason, the A-C art department has airbrushed the signage off of the front of the building which reads "Rural Cooperative Power Association - Owned by Those it Serves." (An almost identical photo, but with the sign intact, appears in the Atomic Energy Deskbook.)

Below, a photo I used to introduce this series but which is nevertheless fairly stunning. This is the cover photo of the 4th quarter, 1962 edition of "Allis-Chalmers Electrical Review."

In all of the old material thus far available, this is the only photo this author has seen that shows Allis-Chalmers technicians (note the A-C emblems on their coveralls) at work inside one of their plants; this is the initial fueling of the Elk River reactor. The caption inside reads as follows: "ELK RIVER REACTOR achieved sustained nuclear reaction in the 4th quarter, 1962, with 41 of its 148 fuel elements.... The station, with its coal fired superheater, is gradually being brought up to its full 22,000 kwe capacity by mid-1963."

The tractor enthusiasts' magazine "Old Allis News" issue of Summer 2007 contains a very interesting first-hand article which includes information from three operators at Elk River. (This great article was written by Mark Rusk and originally appeared in the Upper Midwest A-C Collectors' Club Newsletter.) One very interesting fact appears in this article - the statement by operators that, from the very start, it was known that there was a small amount of coolant leaking into the containment. Clearly, then, the problems with the PACECO-manufactured pressure vessel had either not been fully rectified, or perhaps not even fully discovered. Since the leakage was very small, operation was continued and the plant given its operating license at rated power.

Commercial operation - but only for a short time

The 1964 Annual Report to Congress of the Atomic Energy Commission (published January, 1965) includes the following notation about Elk River:

"During its preliminary test program, the AEC-Rural Cooperative Power Association's boiling water reactor at Elk River, Minnesota, attained its full design 58.2 thermal megawatt, 23,000 electrical kilowatt (ekw) {APR note: This must be gross kwe} power level and a full power, 28 day warranty run was completed March 21. {1964.} This was followed by a 60-day transition run to prepare the reactor operators for plant operation after transfer from Allis-Chalmers to RCPA. In November, the reactor was shut down for visual inspection of the control rods. They were found to be serviceable, and the plant was returned to power operation."

Thus, as we've just read, the Elk River plant was finally fully operational and on the grid roughly seven years after the first project, which saw one vendor dropped and the second one bought out and merged mid-project. The official date for initial power operation was July 13, 1964; the official date for commercial power operation was June, 1965.

In another section of the same "Old Allis News" is a one-page interview with former Elk River technician Donald R. McRae who intimates some of the developmental problems that slowed the Elk River plant's becoming fully operational. Most interesting of these is the fact that the plant's protection and alarm system was originally designed and constructed single-channel, causing many spurious trips and scrams. Technicians, according to McRae, convinced A-C to purchase and install "two out of three" coincidence equipment to make operation reliable.

According to both Old Allis articles and many other sources, the leakage of coolant into the containment remained a constant problem. Although the plant did generate power reliably for several years, it was shut down January 31, 1968 for a detailed investigation into the nature of the leakage. The investigation revealed small or hairline cracks in the vessel and piping, which would have necessitated heavy rework or replacement. This date became the official date for the end of commercial power operation of the Elk River Plant, because the RCPA did not elect to continue operation of the plant after the official AEC demonstration period which would in all likelihood have required the purchase of the plant from the AEC. (A similar set of events, along with problems, dictated the end of life of another well known rural power reactor, that being the one in Piqua, Ohio in that the end of the demonstration period did not lead to purchase by the municipality.)

At this point the Elk River plant was essentially doomed; what remained was the decision process to dismantle it. The first step was to defuel the plant; this was accomplished by September 16, 1969 which is the official AEC date indicating all fuel was shipped offsite. On March 15, 1971, the decision to dismantle the plant immediately was announced by the AEC and RCPA; on March 23, the AEC amended the plant operating contract to include dismantling. The plan for dismantling the plant was developed immediately and issued October 18, 1971; the order to begin dismantling was issued June 5, 1972. The work took roughly two years, with the final site survey being issued July 23, 1974 and the entire Elk River project termination order being issued September 30, 1974. "Rural America's First Atomic Power Plant," as the sign on the pressure vessel had indicated and as RCPA and the AEC had advertised, was gone - in the end, doomed essentially by material problems, economical viability with continued operation by, and eventual ownership by, RCPA not considered.


The site still sees use today, by a descendant of RCPA; Great River Energy now owns and operates plant, today known as the Elk River Energy Recovery Station and which now burns refuse, instead of coal and oil, to generate energy. Even with the addition of new equipment in the place of the long-gone reactor containment, the station is immediately recognizable even today as seen below in a photo taken by Great River Energy.

1:05 PM Eastern Saturday September 24, 2011

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