NUCLEAR PROPULSION WEDNESDAY, MARCH 18, 1964 HOUSE OF REPRESENTATIVES, COMMITTEE ON SCIENCE AND ASTRONAUTICS, Washington, D.O. The committee met at 10:30 a.m., in room 214-B, Longworth House Office Building, Hon. Olin E. Teague (chairman of the subcommittee) presiding. Mr. TEAGUE. The committee will come to order. The committee has taken considerable interest in all forms of propulsion and we are going to begin today on nuclear propulsion. We have Aerojet General, the General Atomic Division of General Dynamics, United Aircraft, Astronuclear Laboratory, Westinghouse Corp., and NASA. We have asked each of you to present an 8-minute opening statement. Then it is going to be necessary to have an executive session. So after each of you have given your opening statement, I would expect the committee to go into an executive session for that portion of other testimony and questions members of the committee might want to ask. Any comments or questions? Would you state your full name and address, and names of the gentlemen with you, for the reporter. Mr. HOUSE. My name is William C. House, vice president of the REON Division, Aerojet General Corp. I am the program director for the NERVA program. I am located at the Azusa plant of the Aerojet General Corp. I have with me Dr. C. C. Ross, vice president, engineering, for Aerojet General Corp. STATEMENT OF WILLIAM C. HOUSE, VICE PRESIDENT OF THE REON DIVISION, AEROJET GENERAL CORP., ACCOMPANIED BY DR. C. C. ROSS, VICE PRESIDENT, ENGINEERING, AEROJET GENERAL CORP. Mr. HOUSE. We appreciate the opportunity to speak to you gentlemen today. A discussion of the state of the art in nuclear rocket propulsion as it is represented by the NERVA engine must embrace at least four broad fields of technology. These are: the reactor, nonnuclear components, test facilities, and vehicle technology. Each area by itself could be the subject of a major discussion. Today I will touch on all four points, but will emphasize the nonnuclear components and test facilities. Westinghouse Astronuclear, who is our partner for th reactor on the NERVA program, will cover this item in more detail The time available for this summary limits the degree of detailed material to be presented. Therefore, I would like to refer you fo more detail to the testimony of Mr. Harold B. Finger, manager o SNPO-the joint AEC-NASA Space Nuclear Propulsion Office-be fore the Joint Committee on Atomic Energy on February 19 of this year and again before the Subcommittee on Advanced Research and Technology, Committee on Science and Astronautics, House of Rep resentatives, on February 26, 1964. As you may recall, in November of 1962 the Kiwi B-4A reactor was tested with resulting damage to the core. It was postulated at tha time that flow through the core probably induced vibration of the fue elements. Component tests and full-scale tests during 1963 supported this postulation and the evidence became conclusive when the failure was duplicated in a cold-flow test. Based on this experience and knowledge, both the Los Alamos Scientific Laboratory and Westing house redesigned their respective core support systems. Both re designs appear to be satisfactory based on the results of the recent cold-flow tests in Nevada. The Kiwi tests were completed in February and the NERVA tests on March 11, just a week ago. We are most pleased with the results. We believe that we understand the problem and that our current design is satisfactory from the point of view of vibration. We were also concerned during the last year with the potential lifetime and reproducibility of fuel elements. Again I am pleased to report significant progress. One of these developments occurred as recently as a few weeks ago and undoubtedly will greatly enhance fuel element lifetime and ease of production. I believe it is important to note that reactor neutronics are well understood for the solid-core graphite-type reactor. This has been quite well demonstrated in recent reactor criticality tests at both Los Alamos and Westinghouse. In addition, reactor control principles are well in hand as demonstrated in the Kiwi B-4A tests in November 1962, where complete control was maintained even when severe reactor damage had been incurred. All this is not to say that all our problems are solved. There are at least three hot reactor tests planned for 1964, and it would indeed be fortuitous if we did not encounter new problems in thermal stresses. recycling capability, or something unforeseen. I do believe, however, that progress to date on the graphite solid-core reactor is such as to guarantee its earlier availability for flight application than any other known reactor type. The nonnuclear components for the nuclear rocket present new problems in that they must withstand the radiation environment and some components, in addition, must function properly at temperatures as low as -425° F., coupled with the radiation problem. One such problem that gave us great concern at the outset of the program was the turbopump bearings. It is not possible to lubricate these bearings with ordinary lubricating oils because these will not withstand the radiation environment. Test results to date are better than we had hoped for. The bearings thin a radiation field for 10 minutes under the same condition with no ail damage. More tests will be conducted this year to increase our conled fidence level. for The turbopump itself presents no particular new problems other than that great care must be exercised to prevent excessive radiation be heating of the parts. There is one problem in connection with hydrohigen flow into the pump which I will touch on later in connection with the vehicle system. M. The pressure vessel for the reactor is also a relatively straightforward engineering development but care must be taken with respect to radiation heating in flanges and bolts. Substantial experience is available from the LASL Kiwi tests. The nozzle has presented more difficulty and the problem centers around the very high heat transfer rates from the hot reactor exhaust to the nozzle cooling system. This, coupled with radiation heating, causes special design problems and fabrication techniques which have been the principal source of difficulty. At this time, however, we have at least three candidate nozzles for use, which gives us fair assurance that one or more of these will be qualified by late spring. The principles of the engine control system design are well understood and borrow greatly from other engine programs. We face again the difficulty though, that our usual temperature and pressure sensors deteriorate in the radiation environment. We have a substantial effort underway to investigate instrumentation in radiation fields, and are hopeful that suitable modifications can be made to improve their life in the NERVA environment. Valves, actuators, and seals which are a part of the engine flow or control system are also subject to potential difficulties in radiation and in the extremely low temperature environment of liquid hydrogen. Our effort in these areas has been somewhat limited, relatively speaking, since we are more confident of our ability to provide solutions. Prudent use of available funding has dictated that we emphasize the more crucial problem areas. It is probable that these items would not pace an engine development program even though some difficulties can well be expected. Interim measures of special shielding and so forth are always available to allow overall systems testing to proceed while the problems are being solved on such components themselves. Proof of the state of the art, of course, is in testing the product and herein lies the importance of test facilities. The high cost of a complete nuclear rocket demands first, that we obtain the utmost data from every test, and second, that each engine be capable of a large number of repeated operations with a further capability of remote adjustment in either the facility or engine. The test facility problem presents potential difficulties from two points of view. First, there is the long leadtime for design, construction, and activation. For example, the first engine test stand (ETS-1) was initiated in late 1960 and will become operational in late 1966 or early 1967. There have been some lags not associated with technology but even assuming a very rapid learning curve and careful scheduling, it would appear that 3 years represents a reasonable schedule for a new test stand. There are no vehicle facili facilities. Westinghouse Astronuclear, who is our partner for the reactor on the NERVA program, will cover this item in more detail. The time available for this summary limits the degree of detailed material to be presented. Therefore, I would like to refer you for more detail to the testimony of Mr. Harold B. Finger, manager of SNPO-the joint AEC-NASA Space Nuclear Propulsion Office-before the Joint Committee on Atomic Energy on February 19 of this year and again before the Subcommittee on Advanced Research and Technology, Committee on Science and Astronautics, House of Representatives, on February 26, 1964. As you may recall, in November of 1962 the Kiwi B-4A reactor was tested with resulting damage to the core. It was postulated at that time that flow through the core probably induced vibration of the fuel elements. Component tests and full-scale tests during 1963 supported this postulation and the evidence became conclusive when the failure was duplicated in a cold-flow test. Based on this experience and knowledge, both the Los Alamos Scientific Laboratory and Westinghouse redesigned their respective core support systems. Both redesigns appear to be satisfactory based on the results of the recent cold-flow tests in Nevada. The Kiwi tests were completed in February and the NERVA tests on March 11, just a week ago. We are most pleased with the results. We believe that we understand the problem and that our current design is satisfactory from the point of view of vibration. We were also concerned during the last year with the potential lifetime and reproducibility of fuel elements. Again I am pleased to report significant progress. One of these developments occurred as recently as a few weeks ago and undoubtedly will greatly enhance fuel element lifetime and ease of production. I believe it is important to note that reactor neutronics are well understood for the solid-core graphite-type reactor. This has been quite well demonstrated in recent reactor criticality tests at both Los Álamos and Westinghouse. In addition, reactor control principles are well in hand as demonstrated in the Kiwi B-4A tests in November 1962, where complete control was maintained even when severe reactor damage had been incurred. All this is not to say that all our problems are solved. There are at least three hot reactor tests planned for 1964, and it would indeed be fortuitous if we did not encounter new problems in thermal stresses, recycling capability, or something unforeseen. I do believe, however, that progress to date on the graphite solid-core reactor is such as to guarantee its earlier availability for flight application than any other known reactor type. The nonnuclear components for the nuclear rocket present new problems in that they must withstand the radiation environment and some components, in addition, must function properly at temperatures as low as -425° F., coupled with the radiation problem. One such problem that gave us great concern at the outset of the program was the turbopump bearings. It is not possible to lubricate these bearings with ordinary lubricating oils because these will not withstand the radiation environment. Test results to date are better than we had hoped for. The bearings in a radiation field for 10 minutes under the same condition with no damage. More tests will be conducted this year to increase our confidence level. The turbopump itself presents no particular new problems other than that great care must be exercised to prevent excessive radiation heating of the parts. There is one problem in connection with hydrogen flow into the pump which I will touch on later in connection with the vehicle system. The pressure vessel for the reactor is also a relatively straightforward engineering development but care must be taken with respect to radiation heating in flanges and bolts. Substantial experience is available from the LASL Kiwi tests. The nozzle has presented more difficulty and the problem centers around the very high heat transfer rates from the hot reactor exhaust to the nozzle cooling system. This, coupled with radiation heating, causes special design problems and fabrication techniques which have been the principal source of difficulty. At this time, however, we have at least three candidate nozzles for use, which gives us fair assurance that one or more of these will be qualified by late spring. The principles of the engine control system design are well understood and borrow greatly from other engine programs. We face again the difficulty though, that our usual temperature and pressure sensors deteriorate in the radiation environment. We have a substantial effort underway to investigate instrumentation in radiation fields, and are hopeful that suitable modifications can be made to improve their life in the NERVA environment. Valves, actuators, and seals which are a part of the engine flow or control system are also subject to potential difficulties in radiation and in the extremely low temperature environment of liquid hydrogen. Our effort in these areas has been somewhat limited, relatively speaking, since we are more confident of our ability to provide solutions. Prudent use of available funding has dictated that we emphasize the more crucial problem areas. It is probable that these items would not pace an engine development program even though some difficulties can well be expected. Interim measures of special shielding and so forth are always available to allow overall systems testing to proceed while the problems are being solved on such components themselves. Proof of the state of the art, of course, is in testing the product and herein lies the importance of test facilities. The high cost of a complete nuclear rocket demands first, that we obtain the utmost data from every test, and second, that each engine be capable of a large number of repeated operations with a further capability of remote adjustment in either the facility or engine. The test facility problem presents potential difficulties from two points of view. First, there is the long leadtime for design, construction, and activation. For example, the first engine test stand (ETS-1) was initiated in late 1960 and will become operational in late 1966 or early 1967. There have been some lags not associated with technology but even assuming a very rapid learning curve and careful scheduling, it would appear that 3 years represents a reasonable schedule for a new test stand. There are no vehicle facili |