23. 24. 25. 26. 27. I call attention to the AEC siting criteria since it specifies thyroid and external gamma dose as the key factors. The literature focuses on radioiodine as the pacing nuclide so far as the radiation threat is concerned and I will concentrate attention on this specific hazard. The consequence data to be made available as a result of the AEC nuclear safety study should be valuable in reassessment of the specific radionuclides to be given priority in siting criteria. The AEC radioiodine criteria for calculating the low population zone (LPZ) stipulates 300 rem to the thyroid and inspection of the TID-14844 document shows that this is the dose to the adult thyroid that is involved. I have suggested on two occasions8 that the Atomic Energy Commission should recast its radioiodine criteria in terms of a lower dose to the infant thyroid. My reasons are: (1) Data available since 1962 indicate that the infant thyroid is sensitive to relatively modest radiation doses. The Bravo nuclear test of March 1,1954 exposed children on Rongelap and Uterik Atolls to radioiodine plus gamma doses in the 200 to 1400 rad range, the high values being calculated on a basis of oral ingestion and the low values corresponding to inhalation? Rongelap children were exposed to radiation hazards terminating with evacuation from the island at a time 36 hours after the Bravo shot. A total of 19 of 25 Marshallese children under the age of 10 at the time of irradiation have exhibited thyroid pathology and 16 have required surgery." Two Rongelapese children exhibited growth retardation due to hypothroidism or lack of function of the thyroid; they have apparently responded to thyroid hormone medication.11 (2) Under accident conditions children would be expected to receive higher thyroid doses from radioiodine than adults because iodine concentrates in the thyroid which is about 2 grams in mass for infants. One would expect a ten-fold higher dose for the infant thyroid than for the 20 gram adult thyroid for the same uptake of radioiodine. Actual thyroid burdens for very young children would be 3 to 4 times that for the adult thyroid when there is common exposure to the same air concentration of radioiodine. This difference is due to the lower breathing rate (cubic meters per day) and a somewhat higher rate of uptake.12 The fetus in utero would be sensitive to radioiodine uptake after thyroid function begins. 10 Communities planning emergency measures for nuclear acci- 10 Part II Environmental Analysis of the Uranium Fuel Cycle, EPA- 9inhalation of Radioiodine from Fallout, DCPD, ESA-TR-72-01 Aug.1972. 12 27. 28. 29. 30. 31. 32. and communities could benefit from having available better estimates of the radiation hazards associated with reactor accidents. While they may be told that the probability of a nuclear accident is very low, they are the risk-takers and they have responsibility for protecting the public health and safety. By way of illustrating the radioiodine threat poential, I have plotted a worst-worst case situation in CHART I. This corresponds to a Class 9 meltdown in a 1,000 Mwt reactor operated for 300 days with release of 25 percent of the radioiodine. Weather inversion (Pasquill Type F) and a 1 meter per second wind is assumed. Doses to the infant thyroid are calculated following I. Van der Hoven and W.P. Gammil113 and J.R.Beattie and P.M. Bryant14. CURVE A corresponds to a 1 hour release at ground level. If, however, a 24 hour release is postulated with containment leaking 1 percent of the radioiodine inside containment, then CURVE B results. ( CURVE D illustrates data corresponding to TID-14844 criteria.) These effluents present a very severe radiation threat but they assume no mitigation; the effect of the latter as estimated for a 100 meter stack is shown in CURVE C. Iodine traps could further reduce this dose. Under certain conditions stack release of radioiodine could result in significant population dosage at greater distances from the reactor site, i.e. beyond the LPZ radius. However, exposure of the downwind population would be distributed over a lengthy time interval and would allow for evacuation of the population An alternative to evacuation would be iodide-blocking, assuming that iodine131 was estimated to be the most serious radiation threat. One must put such a worst case projection in perspective because it combines various worst assumptions. Such combinations result in events of lower and lower probability. I have emphasized the importance of the population-at-risk factor in reactor siting because I believe that it is a conservatism that is independent of other probability factors. I would stress the fact that the AEC safety studies must necessarily analyze reactor safety in terms of safeguard designs. This is only one phase of the problem since such designs must be converted into high quality construction, a process requiring vigilant regulatory inspection. Once plants are complete, reactor safety remains a dynamic matter, demanding great competence in utility operation under regulation to insure that plants are operated safely. As a final thought, knowing that the Committee begins consideration of Price-Anderson extension next week, I would suggest that consideration be given to favoring utilities that site their plants so that the population at risk is minimized. Insurance should relate premiums to risks and I suggest that Price-Anderson should reflect the fact that risk is measured in man-rem and this is a matter of the population at risk. 13,A Survey of Programs for Radiological-Dose Computation" Nuclear 14 "Letter in Nuclear Safety, 11, 490 (1970); see also F.T. Binford, J. Barish and F. Kam, "Estimation of Radiation Doses Following a Reactor Accident" ORNL-4086 (1968). 15. The feasibility of evacuation as an emergency procedure is discussed in "Evacuation Risks-An Evaluation" Environmental Protection Agency, National Environmental Research Center, Las Vegas, Nevada (1974). 24 Jan. 1974 Supplement to testimony--Joint Committee on Atomic Energy I would like to add a proposal to my suggestion that there be a competent professional review or critique of the AEC reactor safety study being conducted by Dr. Norman Rasmussen of MIT. I stated that it would require from 5 to 10 percent of the AEC cost of the Rasmussen activity in order to properly fund an independent critique on a professional basis. I estimated that a sum of $200,000 might suffice to fund such a review and I noted that the American Physical Society had been exploring the funding of such a critique but had not as yet found non-AEC money for such work. I remarked that in my opinion "Environmental money has dried up." It occurs to me that the Committee might consider asking the Office of Technology Assessment for the Congress to undertake such a critique of the AEC study. This could provide a means of providing contract money to professional societies for part of the critique. The Office of Technology Assessment (OTA) could take advantage of analytic work on reactor safety being performed at the University of California at Los Angeles (UCLA) under a National Science Foundation study titled "A General Evaulation Approach to Risk-Benefit for Large Technological Systems and Its Application to Nuclear Power." NSF Grant GI-39416. The UCLA work is headed up by Dr. David Okrent and makes extensive use of fault tree analysis. OTA could also take advantage of fault tree analytic work being performed at Battelle Pacific Northwest Laboratories in connection with advanced waste management studies. AEC Contract AT(45-1):1830. I would suggest that OTA could fit the safety critique into the framework of a more general risk assessment relating nuclear to conventional risks in modern society. Chairman PRICE. The next witness will be Mr. Favret, vice president of the nuclear division of Babcock & Wilcox. Mr. Favret, will you introduce your colleagues, please? STATEMENT OF LOU FAVRET, VICE PRESIDENT OF BABCOCK & WILCOX'S NUCLEAR DIVISIONS, ACCOMPANIED BY JOHN MACMILLAN, GENERAL MANAGER OF THE NUCLEAR POWER GENERATION DIVISION, LYNCHBURG, VA.; GEORGE EDGAR, ATTORNEY, LAW FIRM OF MORGAN, LEWIS & BOCKIUS; DR. DONALD ROY, HEAD OF FUEL ENGINEERING DEPARTMENT; AND JAMES MALLAY, MANAGER OF LICENSING Mr. FAVRET. Yes, sir. Mr. Chairman and members of the committee. My name is Lou Favret. I am vice president of Babcock & Wilcox's Nuclear Divisions. With me today are John MacMillan, General Manager of the Nuclear Power Generation Division in Lynchburg, Va., and George Edgar, our attorney, who is a member of the law firm of Morgan, Lewis & Bockius, who participated in the ECCS hearing, Dr. Donald Roy, who is head of our fuel engineering department, and Mr. Jim Mallay, manager of our licensing activities. Babcock & Wilcox welcomes the opportunity, Mr. Chairman, to appear here today to participate in your continuing examination of the safety of nuclear power reactors and related facilities. Babcock & Wilcox has participated since the outset of the U.S. nuclear program on such projects as Shippingport, Indian Point I, Nautilus and Savannah. Babcock & Wilcox is a major supplier of nuclear steam supply systems, components and fuel for naval and commercial application, and operates related facilities for designing and manufacturing reactor systems and fuel. Approximately 10,000 of Babcock & Wilcox's employees are engaged in nuclear work at sites located in Virginia, Ohio, Pennsylvania, Indiana, Illinois, Michigan, and California. Their activities include the design, manufacture, and construction of nuclear reactors, and they are dedicated to indepth quality assurance and operational safety. Before going to the heart of my remarks, permit me to say a few words regarding Babcock & Wilcox and its commitment to nuclear safety. No one is more directly concerned about reactor safety than we who design, build and install these reactors and operate nuclear manufacturing facilities. Our individual and corporate reputations as responsible citizens and our financial future are dependent upon the continued safe operation of nuclear power plants. Babcock and Wilcox has, and is, making significant commitments in capital and operating funds in nuclear technology, engineering, manufacturing, and on a wide variety of safety-related projects. Babcock & Wilcox's safety-related activities include not only the visible results of extensive analyses and experimentation, as con tained in plant safety analysis reports, but also a wide variety of safety research and development activities, quality assurance programs, and participation in the development of industrial codes and standards. Babcock & Wilcox's consideration of safety must be and is incorporated in all stages of its system design, manufacture, and construction activities including material selection, welding, stress relieving, nondestructive testing, shipping, erection, and function testing. An unprecedented safety record has been achieved through the care of the designers, the thoroughness of the AEC in its technical review, and the expertise of the electric utilities. While this safety record is commendable, the diligence of everyone who is concerned with reactor safety must be maintained as the nuclear industry expands to meet the energy demands of our country. We at Babcock & Wilcox pledge our continuing efforts to extend this record. In today's energy crisis, Babcock & Wilcox has a parallel commitment to insure that nuclear energy is efficiently utilized toward the vital national objectives of self-sufficiency by 1980. While the nuclear industry has achieved an excellent safety record, the efficient utilization of nuclear energy can be most effectively accomplished if government and industry make maximum efforts to standardize reactor systems. An essential prerequisite to standardization is standard safety criteria. Standard criteria should not be subject to reinterpretation or change unless warranted by substantial new information significantly affecting the public health and safety. My testimony today will address the importance of standard safety criteria in this context, using the ECCS issue as an example, and enunciate the principles which we believe should govern the development of standard safety criteria in the future. Based on the hearing thus far we believe information to supplement my testimony would be useful and appropriate. I would like to request that the written testimony including the supplemental remarks be incorporated, and with your concurrence I would like to proceed. THE ROLE OF ECCS IN REACTOR SAFETY Reactor safety begins with the defense-in-depth concept. This can be thought of as three independent levels of safety: 1. The design, manufacture, construction, and operation of equipment to minimize failure probability; 2. The provision of protection systems to safely shut down the reactor in the event of an abnormal transient or deficiencies, without the violation of barriers such as fuel cladding of the reactor systems; 3. And the installation of engineered safeguard systems to prevent an uncontrolled release of radioactivity in the event of postulated design-basis accidents. B. & W. has adhered to this three-level philosophy in its maritime and utility reactor programs. This subject is discussed in the AEC's report on reactor safety, WASH-1250. |