14.53. Many small developmental reactors in a number of countries have been decommissioned without problems. A small (58-MWt) BWR with a 118-ft-high, 85-ft-diameter containment at Elk River, Wisconsin was shut down in 1968 and completely dismantled from 1972 to 1974, with the site converted to a parking lot. The cost was $5.7 million.

14.54. The 6-year decommissioning of the Shippingport, Pennsylvania Station, starting in 1984, one year after shutdown, served as a demonstra­tion of the prompt dismantling option [10]. Although the reactor operated at only a modest rating of about 500 MW(t), the pressure vessel had a diameter of 10 ft, which is comparable to the 15-ft-diameter of present large PWR vessels. Other comparisons indicate that the decommissioning operation was indeed relevant.

14.55. Since the reactor pressure vessel is the largest and the most highly irradiated component in a reactor plant, its removal and disposal is the most challenging decommissioning operation. In the case of Shippingport, it was possible to prepare a monolithic package including the vessel, in­ternals, and concrete shield, remove it from the containment, and ship it by barge to a burial site at Hanford, near Richland, Washington. For another reactor, rail transportation might be necessary. This is likely to require segmentation, which would lengthen the project. Although steam generator removal is also a challenge, there has been ample experience with removal and replacement in existing plants.

14.56. The approximate $100 million cost of the Shippingport project provides a useful reference point for estimating decommissioning costs for presently operating reactors and those to be ordered. However, cost es­timates often show large variations, with site-specific considerations and regulatory uncertainties playing a factor [11]. A logical approach is to include an expense for future decommissioning as part of the annual energy generating costs. For example, in Table 10.2, we have arbitrarily included an annual allowance of $5 million for future decommissioning in the listing of energy generation costs. Considering the time value of money at an annual compound interest rate of 4 percent, this will yield $149 million in 20 years, $280 million in 30 years, and $475 million in 40 years for decom­missioning. Of course, escalation (inflation) could add to the future cost of decommissioning. On the other hand, should this become significant, a higher compound interest rate may be appropriate for the accumulating funds. Since such cost projections are in the range of most estimates, it is reasonable to assume that nuclear power plants will not become an eco­nomic or environmental burden after they have completed their useful life.

GENERAL REFERENCE

Rahn, F. J., et al., “A Guide to Nuclear Power Technology,” John Wiley & Sons, 1984, Chap. 12.

REFERENCES

1. R. G. Rosenstein et al., “Proc. Topical Meeting on Advances in Fuel Man­agement,” Pinehurst, NC, American Nuclear Society, 1986.

2. К. M. Taylor and A. Williams, Trans. Am. Nucl. Soc., 63, 388 (1991).

3. Y. Fujita et al., Nucl. Technol., 95, 116 (1991).

4. R. E. Uhrig, Nucl. Safety, 32, 68 (1991).

5. “National Energy Strategy, 1991/1992,” U. S. Dept, of Energy, 1991.

6. “Final Rule on Nuclear Power Plant License Renewal,” U. S. NRC Report SECY 91-138, 1991.

7. T. E. Murley, Nucl. Safety, 31, 1 (1990).

8. T. J. Griesbach, Trans. Am. Nucl. Soc., 64, 263 (1991).

9. R. Bardtenschlager et al., Nucl. Eng. Des., 45, 1 (1978); R. I. Smith et al., U. S. NRC Report NUREG/CR-0130, 1984.

10. F. P. Crimi, Trans. Am. Nucl. Soc., 56, 72 (1978).

11. K. W. Sieving, Trans. Am. Nucl. Soc., 67, 219 (1993).

INTRODUCTION What Is Needed

15.1. “Next generation” reactor concepts have been developed to pro­vide some enhanced safety and economic features for new plants that may be ordered during the 1990s and subsequent years. However, before con­sidering such designs, we should examine the need for additional generating capacity and the likely competitiveness of nuclear plants in meeting this need.

15.2. New generating plants are needed to replace plants that are retired from service and to meet growth in demand. Need projections have been the subject of numerous studies [1]. In the United States an annual growth rate of electricity sales of about 3 percent during the late 1980s and early 1990s indicates a likely need for additional generating capacity after the year 2000.

15.3. A factor in energy planning is the effectiveness of demand-side management. In such management, utilities attempt to influence customer use patterns in various ways so that the efficiency of utilization is improved.

The term efficiency is preferred to conservation to avoid the impression that energy is being saved by sacrificing the quality of life. For example, lower rates during hours of low demand provide an incentive to shift elec­tricity use away from peak hours, thus making better use of generating capacity. Aggressive programs to help individual customers improve their utilization efficiency are being carried out by many utilities. However, despite such efforts, it is reasonable to assume that the demand will outgrow supply in the near future and that there will be a need for new generating capacity. Such a need must be anticipated some years in advance to allow time for construction. Whether a significant number of nuclear power plants are constructed to meet the energy demand will depend on the resolution of several challenges.

15.4. New nuclear power plants will be built only if both the public and electric utility management are convinced that such new construction is in their own best interest. Public attitudes vary from strongly negative by a militant small fraction to various levels of uneasiness by other groups as a result of the Three Mile Island and Chernobyl accidents and delays in managing high-level wastes. However, motivated by concerns regarding atmospheric pollution and the greenhouse effect caused by fossil-fueled power plants, there appears to be an increasing willingness by those who hold reservations to accept the construction of new plants provided that they would be extraordinarily safe.

15.5. The safety of present LWR reactors is considered completely ad­equate, particularly following numerous systems improvements made as a result of the lessons learned from the Three Mile Island accident. However, the poor economic experience of some utilities has raised some questions regarding the wisdom of new investment for nuclear power plants. Al­though a high rate of inflation during the 1970s, as well as orders unjustified by energy demand, contributed to plant cancellations, poor management, a lack of standardization, and regulatory inconsistencies were factors. Also, for many U. S. operating reactors, plant capacity factors were less than those for similar plants in other countries. Therefore, from the utility viewpoint, there is a need for financial risk reduction.

15.6. New reactor designs with “passive” safety features do not require prompt operator intervention in the event of a wide variety of accidents. In addition, such features permit simplification of many of the safety sys­tems, with consequent cost savings. Therefore, these designs tend to meet both the safety concerns of the public and the utility need for systems of reasonable cost. We will examine the important concepts as well as the utility financial risk matter. As provided by 10 CFR 52 (§12.239), design certification procedures for several of these concepts are in progress.