ML20039E780
| ML20039E780 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 01/04/1982 |
| From: | Spencer G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| Shared Package | |
| ML20039E781 | List: |
| References | |
| NUDOCS 8201110410 | |
| Download: ML20039E780 (2) | |
See also: IR 05000312/1981028
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Docket No. 50-312
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Sacramento Municipal Utility District
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P. O. Box 15830
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Sacramento, California 95813
Attention: Mr. John J. Mattimoe
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Assistant General Manager and Chief Engineer
Gentlemen:
Thank you for your letter dated December 16, 1981 informing us of the
ster,s you have taken to correct Item B of the flotice of Violation, which
we brought to your attention in our letter dated ?!ovember 17, 1981.
Your corrective actions with respect to this item will be verified
during a future inspection.
With respect to your response to Item A of the Notice of Violation,
which we brought to your attention in our letter dated November 17, 1981,
we have considered your response in detail and note the following matters:
First, your September 1,1981, Radiation Exposure, Environmental Protection.
Effluent and Waste Disposal Semiar.nual Report, Section B, Gaseous Effluents,
second paragraph states, "...three abnormal releases of radioactive gas
in this report period."
(emphasisadded) Further, paragraph (2)of
that report section describes the noble gas release on lifting the
vessel head as, "...an unexpected release of gaseous activity...."
(emphasisadded) Our inspector's examination of this occurrence and his
discussion with the Rancho Seco staff established that while gaseous
releases normally occur, and are expected in conjunction with reactor
vessel head renoval activities, the magnitude of this release was unexpected.
Further, the facility staff did not have an explanation for the increase
in the quantity of gaseous activity released.
Second, a reactor building purge was in progress, having been restarted
just prior to the reactor vessel head removal. The increase in gaseous
activity in the reactor building resulted in a termination of the purge.
It is not credible that the facility staff would have initiated the
purge knowing that the head removal evolution would result in termination
of the purge. As a result of the termination of the purge, the reactor
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building ventilated through the open fuel transfer tube to the spent
fuel building, a previously unidentified and unmonitored pathway. The
gaseous activity was then exhausted through the auxiliary building
stack, a monitored pathway.
Inasmuch as the spent fuel transfer tube
was a ventilation pathway, a fact not known or clearly identified until
this occurrence, the release to the spent fuel building was uncontrolled.
In addition, the release through the auxiliary building stack was unplanned
since the normal procedural controls for gaseous releases were not
implemented prior to the release.
The evaluation of the release via
this pathway was retrospective.
It should be noted that the notifications
required pursuant to 10 CFR 50.72(a)(8) are based on the accidental,
unplanned or uncontrolled nature of the release.
Based on our review of your letter and the information obtained during
the inspection, we find that the District reported the release to be
both " abnormal" and " unexpected" (emphasis added), the release followed
an uncontrolled ventilation pathway in the facility and that the release
from Rancho Seco was unplanned. The fact that the release reached-
approximately 85% of the Technical Specification release rate limit for
noble gases gives further credence to the view that the release was
unplanned.
Consequently, the Sacramento flunicipal Utility District is required to
respond to Item A of our flotice of Violation dated flovember 17, 1981 as
specified in that flotice.
Should you have any further questions concerning this inspection, we
will be glad to discuss them with you.
Sincerely,
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G. S. Spencer, Director
Director of Technical Inspection
cc:
R. J. Rodriguez, SMUD
L. G. Schwieger, St100
bcc:
DMB/ Document Control Desk (RIDS)
Distributed by RV:
State of CA (Hahn/ Johnson)
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