needed on safety systems. However, that work will account for only a fraction of the total final design and construction cost. The MHTGR does not yet have the years of operating experience that prove, with required reliability, that the design is workable, and the tritium production goals will be met. The MHTGR will be a first-of-a-kind item based on modular reactor manufacturing technology and a new fuel/target cycle never used for tritium production. The present design may be detailed, however, the design for a new process or technology is subject to many scope and design changes over its development and construction life cycle. These changes have a significant probability to impact cost and schedule. In summary, the HWR concept is based on a mature technology and workable reactor design and fuel/target cycle, with the addition of new safety systems. The MHTGR encompasses a new reactor and fuel/target technology that may suffer the usual problems common to first-of-a-kind projects. Thus, we accept the finding of the ERAB report that the HWR provides less cost and schedule risk. Question: I understand that preliminary cost evaluations performed by the Department attempted to "normalize" the cost estimates submitted by the technology sponsors. Why was the lowest cost contingency applied to the heavy water estimates, even though the designs are the least developed, there is no current basis for safety evaluations and there have been no heavy water reactors built for over 35 years. Answer: Reiterating some of the points discussed above: HWRs are the U.S.' only proven producers of tritium. While an HWR has not been built for many years, they have Some of the concepts have never been built. They are first of a kind with all risks associated with first of a kind. These plus a number of other issues were considered in developing contingency estimates. The new production reactor capacity contingency is not a contingency in the true cost estimator's sense. It was especially designed to consider technology and development risk, in addition to considering the level of design detail. One can have a detailed (down to the nuts and bolts) design for even the most advanced technology. However, this does not guarantee that during the development and construction program the scope and design requirements for the project will not change. It is our assessment that the safety modifications needed for the HWR should not affect markedly the proven viability and reliability of the overall production concept, hence, the technical and cost risks are less. In addition, the baseline cost estimates for an HWR have increased over $500 million during the last few years. It has no steam/electric conversion complexities, and efforts are already well under way which will contribute to the design of a new HWR and, thus, reduce cost and schedule risks; i.e., Question: Do you know if the recriticality issue with respect to the HWR has been resolved and verified with experimental data? If not, how long would this take? If the HWR fuel design had to be changed to overcome the recriticality concerns, could this also require a change in tritium target design? So we'd be back to square one, wouldn't we? Answer: Recriticality is an issue for all reactor design concepts; HWR, LWR, LMR, and HTGR. The possibility exists that under the right accident conditions recriticality could occur. As such, reactor design measures are introduced to reduce the likelihood and impacts of recriticality to acceptable low levels. With respect to the current Savannah River production reactor designs, the recriticality issue was addressed in a number of papers and experiments in the mid-1960's. This information was presented in a session of the Savannah River High Flux Demonstration at the Eleventh Annual Meeting of the American Nuclear Society in Gatlinburg, Tennessee June 21, 1965. The papers concluded that "the control system was satisfactory and that the safety system provided the necessary margins of safety." Regarding the proposed NPR concepts, the recriticality issue has not yet been adequately addressed. The HWR concepts and WNP-1 were the only concepts which had performed any recriticality analysis of the actual NPR core with target assemblies. Two of the concepts, LMR and the MHTGR, assumed there would be no recriticality problems and, therefore, provided little or no NPR specific analysis. For the HWR and the LWR concepts, two approaches to the fuel enrichment--recriticality issue--were proposed. One approach was to utilize the current Savannah River high enriched fuel and target assembly; another was to use a low enriched fuel, equivalent to current LWR fuels, to avoid the potential regulatory effort assumed to be required for the higher enriched fuel. Even for the later case, the amount of effort needed to qualify the proposed fuel assembly was assumed to be minimal since the basic materials, fuel, and target design was not significantly altered. Thus, the HWR would not be back to square one. Regarding the potential impact on the tritium target design, it should be noted that the existing design should be unaltered. Question: In light of the fact that no entity has maintained an HWR design that is consistent with the advances of nuclear technology over the past 30 years, and the proposed HWR designs include a significant number of new design features for which there is no operating or licensing experience, and there are considerable questions regarding the severe accident reviews and analyses that must still be done, do you really believe the HWR option has the least schedule risk? Answer: From a nuclear reactor technology viewpoint, the differences between an LWR and HWR are very well known and understood by today's reactor designers. There is, of course, work to be done in the safety design verification area and no unsolvable problems in doing so appear to exist. Our analyses indicate that the HWR option represents the least schedule risk. Question: The ERAB report indicated that the revenues from the sale of energy can offset a significant fraction of the costs of an NPR. In considering the amount of revenues that might be available, I assume that the DOE took a conservative approach--that is, to forecast the potential revenues on the low side. 1. Is it possible that, in actual negotiations with 2. 3. utilities, the revenues could be significantly higher than Isn't it true that utilities at all of the potential NPR sites have offered to buy power or steam from the plant? I understand that all of the power-producing NPR designs incorporate systems that allow the reactor to continue to produce 100% of the tritium capacity even if the electrical generating plant is out of service? Would this relieve your concern about the "availability" of a powerproducing NPR? Answer: The new production reactor capacity cost evaluation includes a realistic projection for the sale of power, neither low nor high. The evaluation included findings based on an updated report entitled "The Potential Future Value of Byproduct Steam from a New Production Reactor Capacity Based on Four Alternative Technologies and Three Alternative Sites," inputs from direct contacts with the Bonneville Power Administration, The Idaho Power, South Carolina Power, and studies prepared by the Northwest Power Planning Council. In addition, the new production reactor capacity cost evaluation included partial capacity credits over and above fuel offset credits, with a higher capacity credit assigned to modular reactor designs. 1. 2. We do not believe significantly higher revenues over what Both the Idaho Power Company and the South Carolina 3. participating in the power conversion side of a power A 100 percent steam dump does relieve most, but not all Question: The ERAB noted there must be full-scale testing of the proposed LWR target and that it may be difficult to find a commercial reactor in which to test the target. 1. I understand it has been suggested that the WNP-1 plant be converted and then the target tested. Do you know of that plan? If that were to be done, what would happen if the target failed? Since the proposer intends to provide payback to the nation from electricity sales, wouldn't it be DOE's responsibility to continue to operate the WNP-1 reactor even if it were not capable of producing tritium? Is this a wise course of action? 2. I understand the recriticality issue with respect to WNP-1 is supposed to be answered by reducing enrichment in the WNP-1 by 10 percent. Has the safety analysis to confirm that been done? Can you meet tritium goals with this lower enrichment? Answer: The ERAB noted that "final qualification of WNP-1 target rods at full-size in an LWR will likely (emphasis added) be necessary." The WNP-1 target qualifications program will provide a comprehensive approach to qualifying the target assembly. The program includes extensive out-of-pile tests and experiments that will provide all but the final validation of the target. Once these tests are complete and high confidence in the design is achieved, target refinements and optimization could be performed in the fixture in an LWR if needed. This program should produce a target that will be capable of producing tritium in the WNP-1. As the ERAB pointed out, "sufficient testing has been completed to prove the feasibility" of a high temperature target. The engineering design, production, and testing remain to be completed. The question that is raised is the economic and schedule of penalties that would accrue if there are unforeseen problems associated with the refinement process. WNP-1 did a preliminary analysis of the recriticality issue and found that a lower enriched fuel would essentially eliminate the recriticality issue. The analysis that was presented was not as complete as a full safety analysis report evaluation of the issue. However, it provided a good point of reference for future work. The proponents analysis indicated that a 75 percent annual capacity factor was sufficient to produce goal quantities of tritium at the lower enrichment. |