ML20211G010

Mound Lab Fabricated Pu/Be Sources

ML20211G010
Person / Time
Issue date:	06/10/1983
From:	Black K NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:
Shared Package
ML20209B984	List: ML20209B980 ML20211F994 ML20211G010
References
TASK-AE, TASK-N302 AEOD-N302, NUDOCS 8611030138
Download: ML20211G010 (4)

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AE00 Engineering Evaluation Report

• LICENSEE: None EE Report No.AE0D/N302 Date: June 10, 1983 Evaluator /

Contact:

KBlack

SUBJECT:

MOUND LABORATORY FABRICATED PuBe SOURCES EVENT DATE: March 15, 1982

SUMMARY

On March 15, 1982, the Department of Energy notified holders of Pu-Be sources obtained from the Atomic Energy Commission that a source with an unwelded end cap had been discovered. Region I inspected 125 sources and found four out of 125 had removable contamination levels that exceeded background.

AE00 suggests that Regions II, III, IV, and V complete inspection programs similar to Region I's and that NMSS, Division of Fuel Cycle and Material Safety, review a recomendation by Mound Laboratory that the sources be subjected to NDT examinations.

DISCUSSION On March 15, 1982, the Department of Energy (Attachment 1) notified holders of plutonium-beryllium (PuBe) neutron sources obtained from the former Atomic Energy Commission that a source with an unwelded end cap en the outer encapsulation had been discovered. The notice recomended that the sources be inspected.

The Office of State Program obtained a list of RIS symbols defining the firms or institutions to which the notice was mailed. AE00 decoded the synbols and provided to the regions, State Programs, and International Programs lists of NRC licensees and foreign countries to whom the letter was mailed (Attachment 2).

Region I has been making a special inspection of all Region I holders of these sources. During their inspection of 125 sources, they found four sources with remov ble contamina werepessthan0.00gigi levels that exceeded background. The contamination levels AE00 called Mound Laboratory, fabricator of the subject sources. Dr. R. E. Vallee provided the following information.

MLM-1927, " Plutonium-Beryllium Neutron Source Surveillance and Testing," (1973) gives the results of destructive and nondestructive tests on Mound-fabricated PuBe neutron sources.

Mound-fabricated sources fabricated prior to August 31, 1960, were recalled in May 1961. Dr. Vallee provided a list of holders of sources that were not returned. Note that the holders are holders of records in 1961. Attachment 3 gives a list of holders that did not return their sources.

The 1961 recall was prompted by a violent rupture of a PuBe source. In an effort to determine the cause of the rupture, sources were recalled. Of 743 sources.

688 sources were returned. The outer encapsulation of each of the recalled sources l

• This report supports ongoing AE00 and NRC activities and does not represent the position or requirements of the responsible NRC program office.

8611030138 830614 PDR ORG NEXD

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was removed and the inner container tested for leaking (helium leak test). Of 688 sources 142 had leaking inner containers. Leaking inner containers were

rewelded and all sources were welded into new outer containers.

After the 1961 recall, Mound reconinended in 1971 that a sample of the PuSe sources  !

be subjected to leak checks, radiographic and dimensional analysis. The recommendation was based on three instances of potential failure (high levels of removable contamination, two bulging sources). Mound requested that holders of the sources wipe test the sources, check the dimensions, and provide information on i the past and current uses. Approximately 50% of the users responded to the Mound i request.

In 1973, Mound performed destructive and nondestructive tests on 53 Mound-fabricated sources. Thirty-three sources showed potential problems based on the examination.

Mound concluded that sources having a Vega steel outer canister were at greatest risk. The use of Vega steel for outer containers was uncommon, being specified by one customer, Schlumberger.

I In the 1973 document, MLM-1927, Mound reiterated its recommendation that if Mound-i fabricated sources were continued to be used, the sources should be subjected to nondestructive testing evaluations (radiography, leak testing, visual and dimensional checks, and wipe testing). Mound also recommended that Vega steel

! clad sources not be permitted to be used. AE00 verified that Schlumberger was no j longer using PuBe sources.

FINDINGS l

j Region I found that about 4% of the subject plutonium-beryllium sources had removable

contamination levels that exceeded background although the levels did not exceed

! 0.005 Ci of removable contamination (the regulatory definition of a leaking source).

No data have been received from the other regions and no information on leaking j plutonium sources is available in the AE0D nonreactor data file.

The Mound report, MLM-1927, published in 1973, recommended that the subject plutonium-beryllium sources be subjected to the NDT evaluations of radiography, i leak testing, visual and dimensional checks, and alpha wipe testing. The report concluded that continued use of acceptable sources presents a low level of risk based on historical experience, i

RECOMMENDATIONS AE00 suggests that Regions II, III, IV, and V adopt an inspection program with regard to the Pu-Be sources that is similar to that of Region I. With the existing resource limitations, we believe that checking the condition of the sources at the time regularly scheduled inspections are performed is a reasonable program.

l We suggest that NHSS Division of Fuel Cycle and Materials Licensing review the

! history of the sources to determine whether'or not the Mound Laboratory reconinendation contained in the 1973 document, MLM-1927, should be followed.

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o Attachment 3 Holders of Mound-Fabricated PuBe Sources Returned in 1961 North Carolina State Raleigh, NC Armour Research Institute (now IIT)

Birdwell (11)

Bradford, PA; Tulsa, OK Westinghouse Atomic Power Division Pittsburgh, PA ALC0 Products Ft. Belvoir, VA General Atomics San Diego, CA Inland Testing Lab (2)

Morton Grove, IL Stevens Institute of Technology (4)

Hoboken, NJ Anton' Electric Lab Brooklyn, NY Advanced Technology Lab., Division of American Std Mt. View, CA UCLA Los Angeles, CA National Bureau of Standards Washington, DC Various Shipyards U.S. Navy Foreign Countries 4

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ENCLOSURE 1 jo [r.n n6 - -

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Departrnent of Energy MN Richland Operations Office P.O. Box 550 Richland, Washington 99352 TO: ALL HOLDERS OF PLUT0NIUM-BERYLLIUM NEUTRON SOURCES

SUBJECT:

INSPECTION OF PLUTONIUM-BERYLLIUM NEUTRON SOURCES Your organization is on record as having acquired one or more plutonium-beryllium

, (PuSe) neutron sources through a plutonium loan, grant, or sale ad:ninistered by i the former U. S. Atomic Energy Commission (now the Department of Energy). .

The purpose'of this notice is to suggest that you inspect all of your PuSe sources.

to assure t.5at the end caps are welded in place circumferential1y, as requirred by fabrication specifications. Refer to Enclosure 2 as representative of source fabrication. Recently a source was discovered with an unwelded outer end cap which came loose (Enclosure 1). If there is a defect in the inner capsule as well, i

a contamination problem may occur.

i We recomend . inspection' of the outer cap weld by qualified nondestructive testing i personnel. Proper procedures should be used during inspection to assure control

! of radiation and possible contamination. If any problem is detected, notify your licensing authority at once.

l If you should desire to dispose of a PuBe neutron source, you may centact the following office for instructions: .

U. S. Departrcent of Energy .

! Savannah River Operations Office

! Attn: L. C. Sjostrom, Tech. & Prod. Div.

l P. O. Box A Aiken, SC 29801 -

I Infomation regarding source return may be obtained from W. D. Conner, FTS 239-3776,.

. or coranercial 803/725-5211, Ext 3776~. .

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Gecrgel J. M'skho, Director HMP:RER Nucle d b erials Production Division

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Enclosures:

• ~

l 1. Photograph - .

2. Fabrication drawing - .

cc w/ encl.

V. L. Miller, NRC/NMMSS -

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. ,y[ g [M[ Md.

C. Michelson, NRC/0AE00 j .

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