5th. Report, INVESTIGATION OF RADIOACTIVITY of Vessels from Bikini at the San Francisco Naval Shipyard begun 5 September 1946.


5th. Report, INVESTIGATION OF RADIOACTIVITY of Vessels from Bikini at the San Francisco Naval Shipyard begun 5 September 1946.

Progress and further developments In the experiments described in previous reports:

Flashing (with fresh water) of the Firemain section on the LAFFEY which had been treated with pH 6 solution continued through the night of 17 September and was secured early in the morning of the 16th. The blanked off ends were opened up and drippings were collected and put in an add barrel. Photographs were taken of the end sections of the piping, showing the work of the solution in removing marine growth. The results can be summed up by saying that the pH 6 solution was not particularly effective ta removing marine growth, although it is estimated that 90% of the radioactivity was removed.

The second phase of acid circulation in the Firemain forward on the LAFFEY was stepped at 0205 Wednesday, 18 September. Flushing was begun at 0215 and at 0300 the line, contain lug-fresh water, was secured. Samples of acid concentration were taken at intervals and a small reduction at .30 occurred. (1.08 to .79) It is estimated that the acid treatment removed 100% of marine growth and scale, and reduced radioactivity about 98%. Precise figures on the decrease in radioactivity of the acid solution between the first phase and the second phase as well as the monitoring of the piping after the decontaminating solution had been removed are contained in a report by the monitor, Dr. Chadbourn, to Capt. Walsh (MC) who is in charge of the experiments.

Yesterday afternoon short pieces of Firemain removed forward add aft of the section treated with Hydrochloric Acid and were taken up on the main deck for a future decontaminating experiment. The section taken out forward was low In radioactivity, while the section taken aft of the treated line was very high in radioactivity. Seven valves which had been found to be “hot” by the monitor were takes from various parts of the ship and made ready for immersion in a barrel of decontaminating solution (Hydrochloric Add), the valves range from 1 inch to 4 inches IPS, and were taken from systems such as Ice Machinery Overboard Fire and Bilge Pump discharge, Firemain, and Firemain cutouts.

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The experiment in decontaminating galvanized steel pipe aboard the HENRICO was begun, with the mixing of the pH solution (5.95 actual) and the pumping and circulating of it in part of the Flushing system of the troop’s head. Circulation was begun at 1045 and after 45 minutes of circulation, pumping was secured and the solution allowed to stand. It will be blown out 72 hours from the time of securing (1130). The circulation of Hydrochloric Acid (1 normal) was begun at 1455 through a portion of the Flushing system in the troop’s head. The curve of the rate of reaction was watched from hour to hour. Circulation was stopped at some time past midnight and will be detailed in the next report.

The HENRICO asked this Yard to remove a clogged section of pipe in a troop head (2-132) and it was found that this section was extremely radioactive. The section has been removed, and a new section is being put in.

An evaporator and a condenser on the hospital ship, USS BENEVOLENCE, were monitored yesterday by Lt. Comdr. Skow (MC) with expected results. The reading through the evaporator shell was not particularly high, but scale in the evaporator (which had been cold shocked previously) was found to have a radioactive emission double the normal tolerance of human beings for gamma and beta rays. It is considered that in view of this emission rate, 8 hours of work around this type of material should be the maximum. Up to 1800 yesterday no provision had been made by the ship for taking the evaporator scale away from the evaporator room. Attention to this was called by Lt. Comdr. Skow, and provision has been made to have the scale and zincs from the condensers placed on the fantail for eventual disposition at sea. The gratings in the condenser room were found to be extremely hot radioactively in one section, and orders were given to wash the gratings and bilges with Citric Acid.

Rear Admiral Solberg, Captain Walsh, Captain Maxwell, and Captain Lemler boarded the LAFFEY and BENEVOLENCE in the afternoon and examined the results of the experiments on piping. A meeting was held aboard the BENEVOLENCE regarding various decontamination procedures which will be reported upon by Lt. Comdr. Turnbaugh, Assistant Repair Superintendent, who is representing the Yard in such matters.

Clothing issued workmen for their protection is of a winter nature and has been extremely uncomfortable for the days when the hottest weather of the year has prevailed. The Shop Superintendent has ordered more suitable clothing.


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San Francisco Naval Shipyard
San Francisco 24, Calif.
File (335)
16 September 1946
Subject: Radioactive Ships at San Francisco Naval Shipyard –
Status to date

  1. To date the following ships which took part in the Bikini operation have arrived at the San Francisco Naval Shipyard:


  1. Clearance has been received from Captain W. E. Walsh (MC) USN, Radiological Officer for Joint Task Force One, for the above seven ships. By partial clearance is meant the following:

a. All work which does not involve a surface that has been in contact with sea water may proceed normally with complete safety to all workmen and-without special precautions for the men in dressing or cleaning up.

b. Jobs which involve surfaces which are suspect by virtue of their being normally in contact with sea water can be worked only:

(1) When a monitor is present to inspect, . , and issue safety instructions for the handling w each specific job.

(2) When all workmen assigned to each job are properly dressed and instructed and have special facilities available for decontamination,


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To date only one Job has been opened because there has been no monitor to work with the Shipyard.

  1. Captain Walsh is aware of the urgency for having a full-time monitor in the Yard. He has indicated that he will have one or two monitors available for production work beginning Tuesday,17 September,
  2. Captain Walsh with the assistance of scientists from the University of California and from Stanford has directed the following investigations and tests: . (NOTE: When inspection by Geiger Counter showed Beta or Gamma emissions, samples were taken for laboratory analysis of Alpha omission.)

a. Inspection for the amount of radioactivity on the USS LAFFEY in drydocks.
(1) Inspection of barnacles, sea growth, rust, and paint on the underwater body.
(2) Inspection of the evaporators.
(3) Inspection of salt water piping.

b. Experimental sandblasting on the USS LAFFEY to determine’:
(1) Amount of radioactivity in the sandblasted material in the bottom of the dock,
(2) Amount of radioactive material in the air immediately surrounding the sandblaster.
(3) Amount of radioactive matter in the dust stream floating to working areas on deck of the ship and on the side of the dock.

c. Experimental burning of a section of radioactive salt water galvanized steel pipe to determine the amount of radioactive matter in the resulting fumes.

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d. Experimental sandblasting again on the USS LAFFEY, but on a much larger scale than the first experiment.

e. Experimental ‘’deactivation” of a section of copper nickel firemain piping on the USS LAFFEY by means of a solution of acetic acid and ammonium hydroxide – USS HENRICO.

No results of benefit to the Shipyard have been given as most samples are still under analysis.

  1. The Shipyard, in Barracks “B”, has facilities as a “Dressing and Decontamination Center” for 58 workmen. A working procedure has been set up for preparing a man for the job and for safeguards at the end of the shift. These facilities are being expended and include laundry service in the Yard for the government issued safety clothing which the men are required to wear.
  2. Full scale work on radioactive surfaces can proceed as soon as monitors are available to the Shipyard, although the working procedure for certain jobs will depend on the results of the above experiments.

Production Officer

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San Francisco Naval Shipyard
File (335)
San Francisco 24, Calif.
19 September 1946

MEMORANDUM TO: Commander, San Francisco Naval Shipyard, San Francisco.

Subject: Summary of Rear Admiral Solberg’s visit to San Francisco Naval Shipyard on Tuesday, 17 September 1946, regarding experimental work on the Bikini Radioactive Ships.

  1. Before arriving at San Francisco Naval Shipyard on Tuesday, 17 September 1946, Rear Admiral Solberg conferred with Captain Walsh, Radiological Officer for Joint Task Force One, and with Dr. Scott from the University of California. At this conference he was made acquainted with the laboratory results of most of the experiments so far conducted at San Francisco Naval Shipyard. After this conference he visited San Francisco Naval Shipyard to see the experimental work and to discuss with the Production Officer the work in progress. He also asked for further experimental work and inspections to be set up so as to aid on conclusions being reached as to how the shipyard should proceed with each of the problems on the radioactive ships.
  2. The various items covered by Rear Admiral Solberg s visit are summarized as follows:
    (a) That the subject matter of how to rid a ship free of radioactivity should be classified as “Top Secret”.

(b) That the Bureau of Ships in setting up a “Decontamination Section” and that they are interested in and will want information concerning the experimental work being conducted here.

(c) That he will inform the Shipyard on the following day whether or not to go ahead with the sandblasting on the USS LAFFEY. Indications at present are that it is safe.


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(d) That the Shipyard should proceed to set up !or decontaminating the evaporators on the USS BENEVOLENCE, The final order to go ahead would be given after his inspection of these evaporators the following day.

(e) That the Shipyard have the following items ready for his inspection at 1300 on the following day:
(1) Circulation of decontaminating fluids in the two sections of firemain on the USS LAFFEY be concluded and these flushed sections opened up for his Inspection. Also adjoining sections of firemain which had not been decontaminated should be opened as a comparison to see the effectiveness of the decontamination process in removing scale and marine growth.

(2) One evaporator on the USS BENEVOLENCE should be opened to check for radioactivity and to have scale samples for his inspection.
(3) One auxiliary condenser should be opened and a zinc obtained for his inspection.

(f) That the Shipyard remove several salt water valves from the USS LAFFEY to test the procedure of soaking them in decontaminating chemicals in order to clear the radioactivity to the extent that the valves can be safely sent to the shop without any safety precautions in working them.

  1. One item of general interest was the fact that the USS LAFFEY, which had cruised considerably in tropical waters, showed unusual heavy sea growth in her copper-nickel wait water piping. Rear Admiral Solberg stated that he was going to have this matter investigated by the Piping Section, Bureau of Ships.

CC: 203
250 (for file)


Production Officer

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File (336)

San Francisco Naval Shipyard
San Francesco 24, Calif MEMORANDUM TO: Commander, San Francisco Naval Shipyard.

Subject: Summary of Rear Admiral Solberg’s visit to San Francisco Naval Shipyard on Wednesday, 18 September 1946, regarding experimental work on the Bikini Radioactive Ships.

  1. The first phase of Rear Admiral Solberg’s visit on Wednesday, 18 September 1946, was a conference with Admiral Edwards and Commodore Fowler regarding the overall aspect of this problem of radioactive contamination erf ships.

(a) The problem of the underwater body of ships and the urgency of drydocking was to be resolved as follows:

(1) The USS LAFFEY was to be considered the example of the ship least contaminated as her hull showed little radioactivity. having been in Bikini Lagoon approximately ten days. It was noted that she had plastic paint.

(2) The ship having commercial paint which had been in Bikini Lagoon the longest was to be considered the example of the ship with the most contamination of her underwater body. Drydocking of this ship, followed by a careful examination of her hull would yield the necessary comparison with the USS LAFFEY. From this comparison it would develop whether to drydock all Bikini ships immediately or to merely note to cognizant parties, that such ships were to be handled with special precautions at their next normal docking period. Rear Admiral Solberg stated that he would check Bureau of Ships records to pick this second ship to dock.

(3) It was pointed out by Rear Admiral Solberg that graving docks could be used for this work.

(b) The problem of contaminated salt water piping and engineering equipment was to be resolved as follows:

(1) A burning experiment on radioactive piping was being planned. From the laboratory analysis of fume deposits from the


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experiment the danger involved in working radioactive matter could be evaluated. This experiment would represent the extreme condition. This experiment, together with those in process, would yield the needed information on the subject.

(2) The worst conclusion would be that complete decontamination by methods now under experiment at San Francisco Naval Sliipyard, or similar, would be necessary before Yard work could proceed on radioactive ships.

(3) The optimum conclusion would be that no decontamination would be necessary before working radioactive surfaces.

(4) Meanwhile Captain Walsh was to continue to issue “Clearance for Sailing” on the lines of present policy.

This concluded the conference.

  1. Rear Admiral Solberg’s party and interested Yard representatives then proceeded to inspect the experimental work. Important observations follow:

(a) On the USS LAFFEY, the section of copper nickel piping decontaminated by the ammonium citrate standing solution showed that nearly all radioactivity had been removed. However, considerable sea growth remained.

(b) On the USS LAFFEY, the section of copper nickel piping decontaminated by the dilute hydrochloric acid showed 98% of radioactivity removed. Also, all sea growth and scale in the pipe has been taken out.

(c) On the USS LAFFEY, open sections of piping and valves not decontaminated were inspected and -found to be of radioactive intensity below the “tolerance limit”. Samples of radioactive matter were taken by Dr. Scott for further laboratory study.

(d) The USS HENRICO was not inspected because the two steel saltwater piping systems were Under the process of decontamination and not ready for findings.

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(e) The USB BENEVOLENCE evaporators were Inspects. Sample scale showed more than twice the “tolerance limit”. It was decided on the spot to proceed with the decontamination of the evaporators by the hydrochloric acid method.

(f) The USS BENEVOLENCE No. 1 auxiliary condenser was examined. The zincs appeared to have concentrated the radioactive matter. The ship was instructed to replace all zincs immediately. The bilges of the generator and auxiliary condenser room showed undue radioactivity necessitating scrubbing with a solution furnished by San Francisco Naval Shipyard.

A conference was held in the BENEVOLENCE to instruct the ship in the necessary procedures to follow in preparing for sailing.

  1. Rear Admiral Solberg’s party then proceeded to a conference with the Shipyard Commander and the Production and Planning Officers. Summarized items of this meeting follow;

(a) Regarding the USS LAFFEY:

(1) For underwater body, scrape down all barnacles and save for laboratory analysis. Follow with wet sandblast. Do not dispose of sandblasted materials until investigated by monitor.

(2) Try fresh water flushing alone as a decontaminating process on the copper nickel piping.

(3) Remove a 15 ft. section of badly contaminated and badly fouled CuNi piping for a burning test with special control over air current in compartment. This test to be directed by Dr. Walsh or Dr. Scott. Burn in circular cuts as close together as possible. This test should have first priority.

(4) Connect up services to USS LAFFEY.

(b) Regarding the USS BOTTINEAU:

(1) Remove 15 ft. badly contaminated and badly fouled steel piping for burning test as described for USS LAFFEY* This test has first priority

(c) Regarding the USS HENRICO and USS BENEVOLENCE:

(1) Decontaminate the entire salt water system using a flush of fresh water only. Public Works has responsibility of taking all precautions dockside to prevent contamination of Yard fresh water lines. Lieutenant Commander Turnbaugh has same responsibility on ship’s side. Monitors must be given opportunity to check lines before and after process – getting inside as well as outside readings.

(d) Regarding the USS BENEVOLENCE:

(1) The Yard is to proceed with acid decontamination of all three double effect evaporators.

(2) The Yard will furnish information and material necessary for scrubbing down the generator room bilges.

(3) The Yard is to procure six zincs and 200 lbs. evaporator scale and deliver to Captain Walsh for analysis. The ship will dispose of remainder of zincs and scale.

(e) Miscellaneous:

(1) A decontamination procedure on salt water piping using steam and cold water shock followed by flushing should be tried.

(2) Captain Walsh will furnish a summary of laboratory analysis of tests for inclusion in the Yard’s record.

(3) Suitable arrangements for bachelor quarters in the Yard or on board ship was requested for two monitors.

Production Officer
CC: 200
250 (for file)

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