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these coated fuel particles maintain integrity during all normal and licensing basis events and that fission product release from MHTGR fuel is therefore dominated by contamination and manufacturing defects. The MHTGR program has calculated that, assuming stringent fuel process specifications are met, the fission product release even under extremely low probability, severe accident events will still meet the dose limiting regulations, without a need for a secondary leak-tight containment structure. Plant operation and out-of-pile test results, although limited in scope so far, confirm the above performance claim. However, until the fuel demonstration program has progressed further, some uncertainty remains that these particles can be manufactured and inspected on a commercial basis to the quality required and that they will consistently meet integrity requirements under severe accident conditions. Providing confidence that the fuel meets all fabrication and operational expectations is the fundamental key to utility acceptance and success of the MHTGR concept. A comprehensive testing program, possibly including confirmatory result from a prototype plant, is the mechanism which will provide this confidence.

2. The predicted frequency and consequences of bounding events is so low in the MHTGR that no low-leakage containment is provided around the primary circuit boundary. Confirming the predicted frequencies and consequences will require proving not only the fuel quality and integrity as noted above, but also the accident analysis methods and the fission product transport methodology. Even then, it will be difficult to obtain public and regulatory acceptance of the nontraditional containment approach. A fall-back position, specifically one enhancing containment, should be developed so that the design and cost impact can be understood.

3.

Two areas where technical needs and dependent costs may have

4.

been significantly underestimated are in plant manning levels and in spent fuel storage and disposal. The number of operating crews and the number of total plant personnel are less than can be supported by extrapolation from US nuclear plant experience to-date. The spent fuel storage capacity does not allow for the real-life delays to governmental removal of the spent-fuel from the site, and the assumed for the storage facilty and for the storage casks seem inadequate.

costs

The refueling plan for the MHTGR is to replace half the fuel every 20 months. The MHTGR program indicates 21 days has been allotted for the refueling outage. Virtually the entire core is removed from the reactor vessel to a fuel-handling bay. where half of the fuel is replaced as the core is reloaded into the reactor vessel. The number of fuel handling operations is quite large (roughly 1000 fuel and reflector blocks must be handled in a typical refueling) and must be accomplished without misloading and fuel damage. The MHTGR program has spent considerable effort designing the equipment to achieve this high rate of handling by using highly automated equipment, providing limited built-in redundancy and spares, and has some experience base from Fort St. Vrain on which to extrapolate this performance.

Reliability of the fuel handling equipment will be essential to maintaining the refueling schedule and plant availability, and the METGR program will need to provide additional assurance regarding adequacy of the fuel handling and refueling methods.

5. The METGR design offers several attractive characteristics in the safety arena which may justify a premium in the busbar costs. However, the MHTGR project must strive for competitive busbar cost with nuclear and coal-fired alternatives. Based upon the presentations given to the

utility team, and recognizing the potential impact of issues discussed in this report, such as containment, staffing levels, spent fuel storage and disposal, it is unlikely that the visualized MHTGR will be economically competitive with contemporaneous light water reactor plants. Achieving an economically competitive design appears to be the greatest challenge facing the MHTGR project. Accordingly, the utility evaluation team recommends that the economic challenge facing the METGR be recognized and that more emphasis be given to potential cost reducing improvements.

6. Seismic capability has been a special concern for the prismatic cores, made up of large blocks of graphite. One feature of the MHTGR design which helps deal with the seismic concern is the relatively deep embedment of the plant, which may help alleviate the motions and loads caused by a seismic event. The MHTGR program should make the seismic design basis of the plant more fully explicit, i.e., how the various structures, particularly including the core, are designed to provide adequate margins for the seismic events postulated in the design basis.

POST-HEARING QUESTIONS AND ANSWERS

ANDREW C. KADAK

PRESIDENT AND CHIEF EXECUTIVE OFFICER YANKEE ATOMIC ELECTRIC COMPANY

MARCH 5, 1991

QUESTIONS

SENATOR MALCOLM WALLOP (R-WY)

NUCLEAR PROVISIONS OF S.341, "THE ENERGY SECURITY ACT OF 1991,"
DATED MARCH 5, 1991.

QUESTIONS FOR ALL WITNESSES:

The Department of Energy estimates that a combination of increases in demand and
retirement of existing electric generation capacity will require an additional
200,000 megawatts of capacity by the year 2010.

QUESTION la:

Would you agree with Mr. Wolfe's statement that until recently there has been considerable excess electrical capacity in this country, but that this era is coming to an end?

ANSWER:

Yes, I agree with Mr. Wolfe that the era of excess electrical capacity is over. DOE's estimate of approximately 200,000 megawatts of new capacity being required by the year 2010 is a realistic scenario that can be used for planning additional capacity.

In the late 1960's, electricity demand was increasing at about 7% per annum, which was effectively doubling supply requirements every ten years. Thus, utilities with their long planning horizons of 12 to 15 years, were adding large amounts of generation capacity. The oil shocks of the 1970's and increased conservation efforts cut demand increases by over half, leaving utilities with considerable excess capacity. Coupled with excess supply, the regulatory and legal difficulties of siting and building new capacity caused most utilities to throttle back the construction of new generating facilities. However, over time, the nation's economic growth has caused electricity demand to catch up with our excess supply. While it may not be desirable to have excess electricity supply, it is very undesirable to have electricity supply shortages.

There are significant regional indications that demonstrate the end of excess electricity supply. In 1988 there were a series of brown-outs in Massachusetts, that cost its high-tech industry at least $80 million. The warning signs continued in 1989, with rolling blackouts in Texas and Florida during the Christmas season and in 1990 with brownouts/blackouts in the mid-Atlantic states during the summer months. The warning signs are prevailing in 1991. As I mentioned in my testimony, the State of Florida is still experiencing rolling blackouts on cold days. I speak of this with some personal knowledge as while I was speaking to my mother on the telephone last February, her home in Florida, experienced a rotating blackout. This is an unacceptable way for Americans to live. Our nation cannot tolerate electricity shortages while trying to successfully compete with Japan, Korea, and Europe in the economic arena.

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