United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9510310412

                        NUCLEAR CONTAINERS, INC.

       Chemical & Nuclear - Engineering and Equipment Fabrication

            Route 9, Box 2237 - Elizabethton, Tennessee 37643
               Telephone: 615/543-4211   Fax: 615/543-6007

October 26, 1995

Document Control Desk
United States Nuclear Regulatory Commission
2120 L Street NW
Washington, DC 20555

Ladies and Gentlemen:

Pursuant to the requirements of 10CFR21.21, Nuclear Containers, Inc.
(NCI), Route 9, Box 2237, Elizabethton, TN, 37643, hereby officially
reports the existence of defects found in a Model UX-30 overpack,
Certificate of Compliance No.  USA/9196/AF, sold in 1990 by
Nu-Pack (Vectra Technologies, Inc.), 6203 San Ignacio Avenue, Suite 100,
San Jose, CA, 95119.

This overpack was obtained by NCI in 1995 and was tested for additional
baseline information as part of NCI's recent hypothetical accident
testing of NCI-21PF-1 and DOT-21PF-1B overpacks.  These tests included
drop testing, puncture testing and thermal testing as required under
10CFR71.73.  The UX-30 successfully passed all tests, but during
subsequent scrapping operations which began on October 11, 1995, we noted
the following defects:

     1)   The insulating material was found to be nonexistent or charred
          to such a degree that no margin of safety existed following the
          30-minute thermal test; and

     2)   The outer shell suffered extensive through-corrosion at several
          locations.

In order to determine the seriousness of the corrosion, samples of the
outer shell of the UX-30 overpack were sent to Law Engineering,
Charlotte, NC, for further evaluation.  We have now received their
preliminary report which is attached to this document; the formal report
will also be submitted when received.  The Law Engineering report
includes the following conclusions:

     1)   The material of construction is AISI type 304 stainless steel;

     2)   The outer shell suffered severe pitting and intergranular
          stress corrosion cracking; and

     3)   The pitting and stress corrosion cracking are due to chemical
          attack - most likely chloride attack - and were present prior
          to the thermal testing.  (Please note that this final
          conclusion is substantiated by our own findings wherein pitted
          NCI-21PF-1 and DOT-21PF-1B overpacks suffered no discernable
          additional corrosion when subjected to identical thermal
          testing.)

These results indicate much more severe corrosion than that previously
found in NCI-21PF-1 and DOT-21PF-1B overpacks and which caused so much
concern during the past year when evaluated under 10CFR71.43(d).
Therefore, we find it necessary to report these defects under 10CFR21;
since this information was compiled and confirmed to us on October 25,
1995, this report is being submitted within the five-day reporting period
required in 10CFR21.21(3).

Sincerely,

William M.  Arnold
Operations Manager

cc:  Mr.  Carl J.  Paperiello, Director, Office of Nuclear Materials
     Safety and Safeguards

                 LAW
                 ENGINEERING AND ENVIRONMENTAL SERVICES

October 25, 1995

Mr.  William M.  Arnold
Nuclear Containers, Incorporated
Route 9 Box 2237
Elizabethton, Tennessee 37643

Subject:  Report of Metallurgical Evaluation
          UX 30 Shipping Package
          Nuclear Containers, Incorporated
          Elizabethton, Tennessee
          Law Engineering Industrial Services Project 10832-5-0807

Dear Mr.  Arnold:

As authorized by your purchase order 5577-A dated February 20, 1995 and
in general accordance with our proposal 2521ME5 dated February 7, 1995,

Law Engineering Industrial Services has completed chemical analysis and
microscopic examination of Samples removed from a UX 30 shipping package.
This report contains test results and conclusions relevant to the purpose
of our work.

Results of Chemical Analysis

Samples from the top and bottom halves of the outer shell were analyzed
for chemical composition.  The Samples tested meet the chemical
composition requirements of an AISI type 304 stainless steel material.

Results of Microscopic Examination

Samples from the top and bottom halves of the outer shell were mounted,
polished and etched to reveal the microstructure.

The top half, outside shell, outside surface bad pitting and extensive
intergranular cracking.  ne top half, outside shell, inside surface in
contact with the foam had severe pitting and intergranular cracking.

                   LAW ENGINEERING INDUSTRIAL SERVICES
                   A DIVISION OF LAW ENGINEERING, INC.

           2801 YORKMONT ROAD, SUITE 200 - CHARLOTTE, NC 28208
                 P. O.  BOX 19667 - CHARLOTTE, NC 28219
          (704) 357-8600 - (800) 672-6601 - FAX (704) 357-8637

                ONE OF THE LAW COMPANIES (Symbol omitted)

Nuclear Containers, Incorporated                         October 25,1995
Law Engineering Industrial Services Project 10832-5-0807

The bottom half, outside shell, outside surface did not reveal pitting or
cracking.  The inside surface in contact with the foam had both pitting
and cracking present.

Based on the photomicrographs, it is our opinion that the pitting of the
stainless steel is due to a chemical attack.  The intergranular cracking
observed is typical of stress corrosion cracking in austenitic stainless
steels.  The likely corrodent responsible for this is chlorides as
austenitic stainless steels are most susceptible to chloride assisted
stress corrosion cracking.

It is our understanding that this package was subjected to a 30-minute
fire test.  While elevated temperatures tend to accelerate pitting and
cracking, it is our opinion that some or all of the pitting and cracking
existed prior to the fire test.  All of the pitting and cracking observed
could not have been caused during a 30-minute fire test.  The heat of the
fire test may have caused existing cracks to grow deeper or some
accelerated pitting, but pitting and cracking were present prior to the
fire test.

Conclusions

1.   The material of construction of the outer shell of the UX 30 package
     is AISI type 304 stainless steel material.

2.   Severe pitting and intergraular stress corrosion cracking were noted
     in the samples as previously described.

3.   The pitting is due to chemical attack and the stress corrosion
     cracking is likely due to chlorides.

Law Engineering Industrial Services appreciates tile opportunity of
working with you on this project.  If you have any questions concerning
this report please contact the writer at (704)-357-8600.

Sincerely,
LAW ENGINEERING INDUSTRIAL SERVICES

Lakshman Santanam
Laboratory Manager
NACE Certified Corrosion Specialist

LS:mh
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