Citation: OPERATION CROSSROADS, RADIOLOGICAL DECONTAMINATION OF TARGET AND NON- TARGET VESSELS Part 2 pp. 33-41
6th Report, 20 September 1946 – INVESTIGATION OF RADIOACTIVITY of Vessels from Bikini at the San Francisco Naval
Shipyard begun on 5 September 1946.
Work was begun yesterday to implement the decisions of the medical “strategy” board convened aboard the USS BENEVOLENCE on the 18th.
In advance of one of the measures decided upon (flushing with fresh water of the Salt Water Systems of the BENEVOLENCE and HENRICO) a careful check was being made of the Salt Water Lines to insure that proper isolation of sections being worked on at present would exist, and as a corollary, to obtain a maximum flushing effect with only portions of the felt Water system available. All Salt Water pumps were ordered inoperable (i.e. electric pumps are to be disconnected, steam driven pumps to have valves locked).
The decision to conduct a burning test on sections of hot Firemain piping containing considerable marine growth (a top priority job) was implemented yesterday by the selection of sections of pipe from the LAFFEY and BOTTINEAU (Copper-nickel and steel respectively). Dr. Chadbourn, after monitoring the piping, selected the Shipfitters Shop aboard the LAFFEY for the test, and took samples while the burning was being done, RBA equipment was used by the burner and Dr. Chadbourn.
The, senior monitor, Lt. Comdr. Skow, took readings on all three evaporators of the BENEVOLENCE in preparation for the injection of Hydrochloric Acid (1 normal) which will be started this morning. The evaporator room, because of its difficulty of access, for pumps, acid barrels etc. has required considerable effort to prepare. The readings of the evaporator scale are now said to be 5 times tolerance (and hence exposure should not exceed 4-1/2 hours) not 2 times as stated in the fifth report.
BENEVOLENCE crew men who on the evening of 18 September brushed the scale from the evaporators were warned by Dr. Skow to take longer on similar jobs in the future, as due to their haste large amounts of highly active scale were deposited on piping and floor plates beneath the evaporators. Dr. Skow monitored the crew members yesterday afternoon to determine if they had acquired any radioactivity in their shoes, clothing, under fingernails etc. No activity was found.
The pH 6 solution in the HENRICO flushing system piping will be removed Saturday morning at 1100 (72 hours after its insertion). Acid circulation on the HENRICO was stopped at 0300 the morning of the 19th. Flushing as in previous work was performed. A second phase was not planned or carried out as In the case of the LAFFEY. The monitor was unable to get any Indication of radioactivity In the acid cleaned line yesterday morning, indicating the effectiveness of this method. The previous reading had been .4. In a laboratory check on the acid, the beaker became half filled with precipitate (marine growth, corrosion etc.), and it is planned to make a weight check.
The immersion of valves In Hydrochloric aboard the LAFFEY and the decontamination of sections of Firemain out on the main deck is to be accomplished as soon as resources are available.
20 September 1946
From: Rear Admiral T. A. Solberg, U.S.N.
Commander Western Sea Frontier
Subject: Report of activities in San Francisco area from Tuesday, 17 September to Friday, 20 September.
- I arrived in San Francisco Tuesday morning, via NATS, for the purpose of conferring on conditions existing in non-target vessels and assisting in clarifying and developing procedures necessary to establish normal operation and up-keep conditions on the subject vessels. I reported to the Commandant Twelfth Naval District and. later, to the Commander Western Sea Frontier giving such information as I had been able to collect In Washington, D. C., and outlining as far as practicable certain proposals for accomplishing the objective above.
- A careful study has been made of the records available in the San Francisco office. Also conferences have been held with officers of The Naval Ship Yard and with Doctors Rodenbaugh and Newell of San, Francisco, and Doctors Hamilton and Scott of the University of California. All aspects of the situation involving the subject vessels have been discussed at length, including also the medical and legal aspects. A number of tests are underway and certain others are proposed which will give further information in determining the best procedures in all cases.
- A number of conclusions made and proposed decisions are submitted below. On arrival in Washington, I will take the necessary steps to present the full situation to Commander Joint Task Force One and attempt to obtain decisions in substance as shown below. The vessels involved divide themselves naturally into three categories, namely: those remaining in an operative status; those bellow inactivated; and those slated for disposal. The latter category of vessel presents a somewhat different problem in some respects which will be discussed with you prior to my departure Friday.
a. Docking Tests conducted on the U.S.S. Laffey indicate that wet sand blasting procedures on these vessels can be carried out using
present procedures without encountering any hazards. Complete sand blasting of the Laffey will be carried out shortly and the results of the preliminary test will be verified at this time. It is believed that the procedure laid down below can be carried out under absolutely safe and practicable conditions in all navy yards and in all types of dry docks.
(1) Remove all marine growth by careful scraping under wet conditions, preferably as the dry dock is being pumped down.
(2) Collect from the bottom of the dock under wet conditions all of the marine growth so removed, including any found on propellers.
(3) Dump the above material at sea.
(4) If the ship is to be painted or touched up carry out the usual wet sand blasting procedure and collect all sand used, place in barge, and dump at sea.
NOTE: It probably would be safe, from tests made to date, to dispense from collecting sand used in sand blasting and dumping at sea. However, it is felt that the safest and soundest procedure Is to carry out the dumping procedure. Attention is also invited to the fact that this procedure will be carried out only on the first docking of the subject vessels subsequent to their departure from the Marshalls area.
b. Salt Water Lines. It would be highly desirable to decontaminate completely all salt water lines when practicable; however, It is felt that, particularly in the cases of vessel5 which are to remain in an operative status, that there is no immediate necessity for carrying this out. Tests to date have indicated on the ships inspected that all salt water lines can be used normally and that all normal routine repairs involving extensive cutting and welding can be carried out without encountering-any hazards to workmen. However, it is considered that one minor restriction must be placed on salt water piping systems in order to be on firm ground in all respects. 1 This restriction involves only instructing each vessel that, in case any section of salt water piping is renewed, the affected section must be sunk at sea. This will obviate any possible danger which may not have been determined.
c. Evaporators. In some vessels at least because of the mass or volume of scale which is present, there exists also the possibility of the greatest amount of active material being present. Consequently, It is
considered necessary that acid cleaning of all evaporating units of these vessels should be carried out once and as soon as practicable and preferably while the vessel Is at sea or perhaps in an open roadstead.
d. Acid cleaning was formerly an accepted method of cleaning but, at the present time, is restricted by the Bureau of Ships. However, I am certain that the Bureau of Ships will accede to one acid cleaning in the case of all these vessels. Acid cleaning will remove all scale in a much
more thorough manner than mechanical or other type of cleaning. I personally authorized cleaning of the evaporators of the Benevolence and the Henrico because of their early departure subsequent Overhaul.
d. Boats Consideration of recent information and tests indicates that the decisions made with regard to disposal and sinking of small boats probably was unnecessary. It is considered that any boats which have not been disposed of as a result of these decisions should be remonitored and decisions made on the basis of information now available.
- As stated above, I will take up the matter of clearance for these vessels as soon as I arrive in Washington and can contact all of the agencies involved. This also will include obtaining concurrence of Manhattan District. It is believed that, in case of the Benevolence and the Henrico, clearance should be given to these two vessels prior to sailing whether or not definite instructions have been promulgated from Washington.” The following type of clearance in these two cases is suggested:
“U.S.S. Benevolence cleared radiologically for all operations with the following exceptions and additional instructions.
ABLE. Salt water piping can be repaired using any welding and cutting operations necessary either by ship’s forces or in ship yards. BAKER. Whenever a section of salt water piping, a fitting, or valve must be renewed, the unit removed shall be retained and thrown overboard at sea. CHARLIE. At first opportunity at sea flush out all salt water lines at each outlet
separately at high water velocity for one-half hour. DOG. Evaporators can he opened and cleaned whenever necessary. EASY. Methods of procedure involving the first docking subsequent to 25 July 1946 are being furnished; to your vessel and all yards under separate letter.
- Captain Walsh, (MC) QSN, and Major Brundage, MC, USA, were present at all conferences and the subject matter above has been discussed thoroughly with them. Both concur in the recommendations contained herein.
MEMORANDUM TO: Captain Walsh 20 September 1946
Subj: Decontamination tests under way at Naval Ship Yard and University of California.
- The following tests are either under way or will be started as soon as practicable. These tests all have as their objective obtaining information on methods of decontamination oi non-target vessels in order that unrestricted clearance for both operations and repairs can be authorized to the greatest extent possible.
a. Tests of short sections of piping which have marine growth present and show measureable activity are being made using the citrate solution, the one normal acid solution, and also plain fresh water. – The solutions are being circulated through the piping at a slow rate and readings taken periodically to determine the effects obtained. The tests involve both copper nickel and ordinary steel or wrought iron piping obtained principally from the U.S.S. LAFFEY and the U.S.S. Henrico.
b. Tests to determine the maximum amount of cutting and welding which can be performed on both copper nickel and steel piping. Sections of piping are being obtained from the LAFFEY and the HENRICO and being cut into small circular sections in a small enclosed space. Samples of the air in this space are being passed through a filter for subsequent analysis of the filter contents to determine whether any harmful materials are present and in what concentration.
c. Tests of small sections of copper nickel and steel piping to determine strength of solutions necessary in order to obtain desired results. Laboratory tests are to be made as soon as specimens can be obtained, using small samples of copper nickel and steel piping which have marine growths and measureable activity. The purpose of this is to determine the most desirable strength of solutions necessary in the case of citrate, boiler compound, and acid in order to remove marine growths expeditiously.
d. Tests for decontamination of salt water systems. – Arrangements are being made to conduct a large scale test on decontaminating
the salt water piping system of the USS BARTON. The chemicals to be used are dependent on the results of Paragraph (c) above, but it is proposed in the first test to use the citrate type of solution. It is planned to reduce the number of outlets in the salt water system so that the amount of circulation will be relatively small and to inject into the suction side of the salt water pump the necessary strength of solution to establish conditions found desirable from (c) above. This will require, once the test is started, opening all outlets in the salt water system in succession for a short period of time until it is evident that the entire salt water system contains the desired strength of solution. This does not involve putting the salt water system out of commission as it will be in use on a restricted basis having only those outlets absolutely necessary open. Outlets from risers should be opened periodically for short periods in order to allow a new solution to enter these risers. It is planned to remove certain valves or short sections of piping prior to and subsequent to the test in order to determine the
conditions existing under both conditions.
e. Tests of evaporators. Use of the Bureau of Ships method of cleaning evaporators using muriatic acid is being authorized for the USS BENEVOLENCE and the USS HENRICO. The evaporator and associated units will be monitored and inspected before and after the tests to determine that the results desired have been achieved.
f. Tests of sand subsequent to sand blasting. Samples of sand used in sandblasting the USS LAFFEY will be obtained for critical examination in order to determine whether or not contamination is present.
- The above tests are for the purpose of determining as soon as practicable the best possible method for complete decontamination of salt water systems in ships. Other tests underway may not make it necessary to follow decontaminating procedures on all vessels, but It is visualized that this may be required on at least some of-the vessels involved.
- Captain W. S. Maxwell and Commander Shirley will remain In the San Francisco area to assist the Naval Ship Yard and also to assist Captain Walsh in any way possible in these projects. It is also probable that Commander Hoffman will be ordered from Washington both for the purpose of assisting in this work and in order to obtain experience with the methods developed.
CC: T. A. SOLBERG
Capt. Lemler, U..S. Naval Rear Admiral, USN
Ship Yard, San Francisco.
Commander Western Sea Frontier
Commandant 12th Naval District.
R R R
SNFH V SNC NR G 247/19 R
FROM CONWESSEAFRON 200054Z ;
TO NAVY SHIP YARD SAN FRAN
UR SPEED LETTER /200-30207/ DATD 18 SEPTEMBER X ONE ACID CLEANING OPERATION AUTHORIZED FOR BENEVOLENCE AND HENRICO X USE METHOD AND MATERIALS PRESCRIBED IN MANUAL OF ENGINEERING INSTRUCTIONS X OBTAIN SAMPLES OF SCALE BEFORE CLEANING X HAVE MONITORS OBTAIN READINGS OF EVAPORATORS AND ASSOCIATED UNITS BEFORE AND AFTER CLEANING X DUMP SCALE REMOVED BY HAND PRIOR TO CLEANING AT SEA X INFORM CAFT W E WALSH MC USN OF RESULTS
0300/20 SEPT BP A 200
1 100 210 300 330 301
Source: OPERATION CROSSROADS. RADIOLOGICAL DECONTAMINATION OF TARGET AND NON-TARGET VESSELS. VOLUME 2 , DNA ltr, 21 Apr 1982, THIS PAGE IS UNCLASSIFIED, DIRECTOR OF SHIPTECHNICAL INSPECTION REPORT. Radiological Decontamination of Target and Non-Target Vessels, VOLUME 2 OF 3.