Dr. TAPE. I spent a day in Japan as I was on my way to Korea and to Taiwan to discuss with the Koreans and the Chinese their own electrical energy program and the possibility of nuclear power in those two countries. USS "SWORDFISH”. –RADIOACTIVITY IN SASEBO HARBOR, JAPAN Representative HOSMER. On the date of May 6, 1968, it was alleged that the U.S. nuclear submarine Swordfish caused some radioactivity to appear in Sasebo Harbor, Japan. Did you have any conversations with any of the Japanese relating to this? Dr. TAPE. No. The discussions that I had with the Japanese-and I talked with the Chairman of their Commission and some of their Commissioners-were confined to their nuclear power program. We did not discuss the Swordfish, or Sasebo incident. I am, I will say, familiar with it; I think most of us are. Senator GORE. I hope the Congressman will afford the Commissioner an opportunity to state the facts. Representative HOSMER. Yes. REPORT OF MAY 25, 1968, BY TECHNICAL REVIEW BOARD Will you do so, and also state whether you are familiar with the report of May 25, 1968, by a review board consisting of William Wegner, Deputy Director, Division of Naval Reactors, AEC; Murray Miles, Chief, Nuclear Technology Branch, Division of Naval Reactors, AEC; and William Givens, Special Assistant to the Deputy Director, Division of Naval Reactors, AEC. Dr. TAPE. Yes, I am, Mr. Hosmer. When we first heard of the difficulties and the allegations of radioactivity present in the harbor, we were very much concerned; this was quite surprising to all of us. We are well aware of the procedures that are followed by the submarines in ports such as Sasebo. It seemed prudent to us to respond to Ambassador Johnson's request that there be technical people sent to Japan, rather promptly, to try to assist the Japanese and to arrive at a better understanding of what actually did take place. Representative HOSMER. That was done promptly in the period May 14 through May 25. Dr. TAPE. That was done promptly, and the team dispatched consisted of the individuals whom you named, headed by Mr. Wegner. The report of Mr. Wegner's group was provided to the Ambassador; I think you noted the date of May 25 of this year. I have examined the report. I have had the opportunity to go over it with Mr. Wegner. The summary and conclusions that they have expressed there reflect our views. We see no reason to disagree, and, in fact, believe that they have done an excellent job of running down all the possibilities that might have occurred. Representative HoSMER. To refresh your memory, Dr. Tape, were the findings as follows? 1. There is conclusive evidence that the U.S.S. Swordfish did not at any time, while in or near the Port of Sasebo, during the period May 2 through 11, discharge reactor coolant or radioactivity of any kind to the atmosphere or to the surrounding waters, and 2. The abnormal readings noted in Sasebo on the morning of May 6, 1968, were not caused by radioactivity discharged from the U.S.S. Swordfish. Dr. TAPE. Those are the two conclusions noted by the committee; and, in my examination of the report and discussions, it seems to me that these are perfectly valid conclusions, Mr. Hosmer. Representative HOSMER. Would you say that they are unassailably correct? Dr. TAPE. Yes, I would. The point that should be made here is that not only did this committee look into the technical facts, but they also had independent Navy auditors, if you will, looking at the logs of the Swordfish and looking at the records and questioning the people concerned. The indications showed that the nuclear powerplant was not in operation during the entire period in the harbor and if one looks through the report one will find details of this kind, which make it rather difficult to arrive at any other conclusion. I think the unfortunate situation here, Mr. Hosmer, is that there were readings of some kind on some monitoring instruments which were being used to check for radioactivity. No one has been able to specifically pinpoint what might have caused, or what did cause, those particular readings. So, from a technical point of view, it is unsatisfactory that we have not been able to pinpoint the cause and say, for example, that a particular radar set which was shining on this equipment at that time did cause these readings because the particular conditions existing at the time could not be repeated. So, from a technical point of view, I think it is a little unsatisfactory that one cannot say specifically what did happen. On the other hand, all the studies, examinations, and work which have been done to date would make the possibility of radioactivity from the Swordfish look, rather, as a poor reason. Senator GORE. Were there no samples taken? Dr. TAPE. There were no samples taken at the time, Senator. This is part of why I say it is unfortunate from a technical point of view that one does not have evidence that one can go back and check. There were no samples taken at the time so that people could do an analysis at a later date. I did not come back through Tokyo on Sunday. I was there overnight on Saturday and left Sunday morning. I picked up the newspaper on Sunday morning. I am not a person who likes to quote to a committee material from a newspaper because I realize that this is not always a good source of information, but I think you might be interested that in the Japan Times of Sunday, June 23, there is a headline "High Radioactivity Counts Found Before N-Sub Visits." Let me read a paragraph or two and I will give you the rest for the record. Unusually high radioactivity counts have often been recorded in the waters of Sasebo Bay even before the first U.S. nuclear submarine called at the port in November 1964, it was disclosed Saturday. (The complete text of the article follows:) [From Japan Times, June 23, 1968] HIGH RADIOACTIVITY COUNTS FOUND BEFORE N-SUB VISITS SASEBO (Kyodo)-Unusually high radioactivity counts have often been recorded in the waters of Sasebo Bay even before the first U.S. nuclear submarine called at the port in November 1964, it was disclosed Saturday. The revelation came amid rising opposition here against visits by U.S. nuclear submarines triggered by the report of a high radioactivity reading in Sasebo Bay while the U.S. nuclear submarine Swordfish was in Sasebo Port last month. The announcement was made by the Sasebo Public Health Center which started measuring radioactivity in the bay water in October 1964 in preparation for the visit of U.S. nuclear submarines. According to the center, 6.25 micromicrocuries (mmc.) of radioactivity was detected in one liter of sea water at the No. 1 monitoring post on Oct. 14, 1964. The post is near where the nuclear submarines berth when in port. The same day, 20.24 mmc. of radioactivity was recorded in the sea water at the No. 15 checkpoint near Kuroshima, and on Oct. 20 a high count of 41.8 mmc. was registered at the mouth of the River Sasebo and at the No. 2 monitoring point in the port. The first U.S. nuclear submarine to visit Japan, the Seadragon, entered Sasebo Port one month later. The highest reading while the Seadragon was in port was 1.35 mmc. The Sasebo Public Health Center also said that 14.36 mmc. of radioactivity was detected near the Saikai Bridge outside Sasebo Bay Dec. 11, one month after the Seadragon's departure. According to the center, these high counts of radioactivity were detected in water near the seabed. It added that high radioactivity readings were usually obtained in waters in the estuary of the Sasebo River and near the Saikai Bridge. The center said the high radioactivity count in one case might be ascribed to an accumulation of natural radioactivity and fallout from the Chinese nuclear explosions. The Communist Chinese detonated their first nuclear device on Oct. 17, 1964. An assistant professor of radiology at Kyushu University said that 40-50 mmc. of radioactivity could not be called "high," and was not harmful to human beings. But he warned against the consumption of fish and shellfish caught in the sea water where high radioactivity was recorded because the radioactivity would be concentrated 10,000 to 20,000 times in living organisms. Representative HOSMER. Mr. Chairman, I ask unanimous consent that the Wegner report be included in the record at this point. Senator GORE. Yes, that will be ordered. (The report referred to follows:) REPORT OF FINDINGS OF THE AEC'S TECHNICAL REVIEW GROUP U.S. ATOMIC ENERGY COMMISSION, AMERICAN EMBASSY, Place: Tokyo, Japan, and Sasebo, Japan. Mr. William Wegner, Deputy Director, Division of Naval Reactors, Mr. Murray E. Miles, Chief, Nuclear Technology Branch, Division Naval Mr. William L. Givens, Special Assistant to the Deputy Director, Division I. PURPOSE To review all technical information available to determine the possible cause of abnormal readings on instruments used by the Government of Japan to monitor environmental radiation levels in the harbor of Sasebo, Japan. The abnormal readings were noted on the morning of May 6, 1968 at the same time the nuclear powered submarine, USS Swordfish (SSN 579) was in that port. II. BACKGROUND On May 6, 1968 Japanese authorities advised the United States Embassy that monitoring of Sasebo Harbor on the morning of May 6 showed radioactivity levels above normal in air and water about 100 meters from Swordfish. It was further reported that the monitoring boat took three separate five minute readings between 10:00 and 10:30 A.M. The first reading showed an average of 1441 counts per minute (cpm) in air and an average 85 counts per second (cps) in water. The second reading showed 468 cpm in air and 35 cps in water. The third showed 557 cpm in air and 36 cps in water. Normal readings were reported to be between 56 and 72 cpm in air and between 4.2 and 5.1 cps in water. The Japanese authorities advised the Embassy that the monitoring boat had taken water samples which were sent to Tokyo for analysis. U.S. authorities in Washington, upon being informed of the above reported abnormal readings, requested local Navy officials in Sasebo to take and dispatch immediately a series of water and bottom mud samples to the United States for analysis to determine if any changes had occurred since the April 1968 series of tests. The April 1968 tests showed no contamination. Results of the May 7 analysis are discussed later in this report. Inquiries immediately were dispatched to the Commanding Officer of the USS Swordfish to determine if at any time while the ship was in Sasebo Harbor from its arrival on May 2, 1968, it had discharged any radioactive material. Results of this inquiry and further investigation are discussed later in this report. On May 13, 1968, the U.S. Ambassador to Japan requested technical representatives from the United States be sent to Japan to assist the Japanese authorities in finding the probable cause of the abnormal readings. The threemember Technical Review Group departed Washington, D.C. the morning of May 14, 1968 and arrived in Tokyo on the afternoon of May 15, 1968. III. SUMMARY OF EVENTS The following information bearing on the reported abnormal readings in Sasebo has been obtained from various U.S. and Japanese sources during the period May 15 through 22 by the Technical Review Group. A. The USS Swordfish (SSN 579) entered the port of Sasebo at approximately 8:00 A.M. local time on May 2, 1968 for logistic support and rest and relaxation. The Swordfish moored with the bow to south on the starboard side of the USS Ajax (AR 6). The USS Ajar was moored midway between buoys 1-N and 1-S, bow to north. Depth of water at mooring is approximately 30 feet (lowest low water). At the time of the abnormal readings the depth of water at the mooring was approximately 35 feet. Nearest land to the Ajar was approximately 150 meters to north. See chart, enclosure (1).1 B. At 9:30 A.M. on May 6, 1968 a small boat (approximately 20 feet long) operated by the Government of Japan, fitted out with environmental monitoring equipment and manned by representatives of the Japanese Maritime Safety Agency (MSA), began a circling operation around the moored Ajax and Swordfish. The monitoring boat made 5 complete circles of increasing radius around the moored ships. Its closest approach to the Swordfish was about 30 meters. Each circle increased its distance from the ships by approximately 20 meters. C. The following information on the monitoring equipment which registered the abnormal readings has been provided by Japanese authorities. The monitoring boat carries two separate pieces of monitoring equipment. One is a GeigerMueller (G-M) radiation detector mounted 1.5 meters above the surface of the water. The detector tube is 2 cm in diameter, 17.8 cm in length and has a wall thickness of 50 milligrams per square centimeter. It is mounted inside the plastic cabin of the boat. The output of the detector goes to a scaler which is read, recorded and rezeroed every five minutes. The instrument check consists of a standard 50 cycle/second test signal. The G-M detector will read 1000 counts per minute in a 0.15 mr/hour field of 1 Mev radiation. The other instrument is an underwater monitor consisting of a sodium iodide scintillation counter, 1.75 inches in diameter and 1.5 inches long. It was towed at a depth below the water of 1.5 meters at a speed of 2 to 2.5 knots. The output of the scintillation detector is continuously recorded in counts per second (cps) on a strip chart. In uniformly contaminated water containing 3 x 10 μc/ml of 1 Mev radioactivity the detector will indicate 75 cps. 1 Enclosures are set forth in app. 5, p. 154. The power supply for both monitoring instruments is a 300 watt gasoline engine driven generator, 100 volt AC. D. The attached charts (enclosure (2)) received from Japanese authorities show the numerical readings taken versus time and harbor position. The highest reading recorded from the G-M detector was 1441 counts per minute-normal background was about 60-70 counts per minute. The highest reading recorded from the scintillation detector was 74.8 counts per second-normal background was about 5 counts per second. Both instruments recorded their highest readings at 10:07 A.M. while the monitoring boat was 100 meters off the port bow of the Ajax. The monitoring boat again circled the Ajax and at 10:17 was again at the 10:07 position. Normal readings were noted at 10:17. The monitoring boat made a small circle (40 meters) returning to the same 10:07 position. It then aproached the bow of the Ajax, turned to the north, passed around buoy 1-N and proceeded back to its base. Peak readings were noted from the scintillation detector at the following times: Reading Time (a.m.): (cp8) Peak readings from the G-M detector were noted as follows: 10:05-10:10 10:10-10:15 10:20-10:25 11:00-11:05 11:05-11:10 16. 0 12.5 13. 0 6.0 9.0 1 Highest reading. E. The following is a list of ships which were in the port of Sasebo on the morning of May 6, Enclosure (1) indicates the location of these ships in Sasebo harbor. Included is a listing of electromagnetic emitting equipment on each ship which is known to have been operating sometime during the period the monitoring boat made its survey on May 6. It has not been possible to determine the exact time each piece of electronic or electrical equipment was being actively used rather than just being energized. For example, the radar on board USS Tulare is known to have been tested periodically during the morning of May 6. Yet no records were made as to the precise time the antenna was radiating. Operating equipment Ship 1. U.S.S. Peacock (MSC 198) ---- Radar, sonar, fathometer, degaussing, radio IV. U.S.S. "SWORDFISH" AS A POTENTIAL CAUSE Potential Cause.-The Japanese Radiation Experts Council has stated that discharged reactor coolant from Swordfish could have caused the abnormal readings of the monitoring equipment. Evaluation. A number of factors were evaluated in considering potential cause before conclusive evidence was available that USS Swordfish did not discharge. These were discussed in detail in meetings between the Technical Review Group and the technical representatives of the Government of Japan |