United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9709250231

3M Health Physics Services    3M Center, Building 220-3W-06

                              PO Box 33283

                              St. Paul, MN 55133-3283

                              612 736 0498

                              612 736 2285 Fax

September 18, 1997

U.S. Nuclear Regulatory Commission

Region III

801 Warrenville Road

Lisle, IL 60532-4351

Attention:     Ms.  Patricia J.  Pelke

               Nuclear Materials Licensing

Dear Ms.  Pelke:

Subject:  Failure of Co-60 Source to Lower in Response to Fault

          Indications and Emergency Stop Signals.

The attached report documents the August 12, 1997, event at 3M's

Brookings, SD irradiator in which the source failed to return to the

storage pool in response to numerous fault indications and emergency

stops.  Per your request and that of Mr. Baggett on August 20, we are

submitting this report under 10CFR36.83, although we feel the situation

is more properly considered under 10CFR21 for the reasons specified in

the report Also per 10CFR36.83, we notified Mr. Chauncy Gould of the NRC

Operations Center of this event on August 20.

Please feel free to contact Mr. Frederick B. Entwistle or me of this

office at (612)736-0740 or (612)733-3199 respectively, with any questions

or comments.


Deborah A.  Loeser

Health Physics Specialist

c: U.  S.  Nuclear Regulatory Commission - Washington, DC


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