ML20039E784
| ML20039E784 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 12/16/1981 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| Shared Package | |
| ML20039E781 | List: |
| References | |
| NUDOCS 8201110417 | |
| Download: ML20039E784 (3) | |
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~ SACRAMENTO MUNICIPAL UTILITY DISTRICT O 6201 S Street. Box 158Y. Sacramento, California 958d (916) 452-3211
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December 16, 1981 y:,
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R H ENGELKEN, ADMINISTRATOR REGION V 0FFICE OF INSPECTION & ENFORCEMENT i
U S NUCLEAR REGULATOPY COMMISSION 1450 HARIA LANE SUITE 210 WALNUT CREEK CA 94596 DOCKET NO. 50-312 REPLY TO IE INSPECTION REPORT 81-28 In reply to the inspection conducted by Mr. H. North on September 21-22, 24-25, and October 6-9, 1981, we offer the following information.
Appendix A of your letter notes the following violations:
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A.
10 CFR 50.72 states in part:
"(A) Each licensee...shall
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notify the NRC Operations Center as soon as possible and in all cases within one hour by telephone of the occurrence of any of the following significant events and shall iden-tify that event as being reported pursuant to this section:
..(8) Any accidental, unplanned or uncontrolled radio-active release.
(Normal or expected releases from mainte-nance or other operat ional activi t ies are not included)."
Contrary to the above, on February 11, 1981 a release to unrestricted areas of approximately 2L1 curies of radio-active noble gas, principally Xenon-133, occurred when the reactor vessel head was removed in preparation for the fourth refueling outage. The quantity of radioactive gas released was approximately 85% of the Technical Specification instantaneous release limit. A number of individuals reported that while releases were normally expected concurrently wi-h reactor vessel head removal, a release of this magnitude was not expected.
The release resulted in automatic termination of the reactor buiing purge then in progress.
The subsequent release of gaseous activity from the reactor building was via the fuel transfer tube to the spent fuel and auxiliary building, a previously undent i fied vent ilation pathway, and i ts subsequent release through the auxiliary building stack.
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The Commission was not notified of the event prior to
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receipt of the 1981 semiannual Effluent and Waste Disposal
. Report, dated September 1, 1981.
8201110417 820104 DR ADOCK 05000312 PDR AN ELECTRIC SiSTI" E R VI N MORE THAN 600.000 IN THf HEART OF C A L I F O R fi i A l
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fI R. H. Engelken Occcmber 16, 1981
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.B.
Technical Specification, Appendix B, Section 2.6.4.B states 'In part:
" Caseous releases to the environment,
...shall be continuously monitored for gross radio-activity, and the flow measured and recorded. -These releases originate f rom the reactor building stack, from the auxiliary building stack, and from the radwaste service area fan (EF-A-9)..."
Contrary to the above, at the time of the inspection the l
flow f rom the reactor building stack and the auxiliary building stack were not being continuously measured and recorded. The radwaste service area fan (EF-A-9) is not in service.
District Reply item A The District does not agree with the basis or conclusion of this item.
10CFR50.72 clearly states that " Normal or expected releases f rom maintenance or other operational activities are not included" under the provision of that section.
Certainly the lif ting of the reactor vessel head is acknowledged throughout the industry as an event which
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may release some gaseous radioactivity. Procedure M.1, " Reactor Vessel
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Closure Head Removal and Replacement" required that two radiation monitoring devices (ei ther remote reading or hand held) be operating on the canal floor on either side of the head prior to lif t; also that -
all personnel in the Peactor Building are given notification that the head is being removed.
Because of potential releases, it is common practice to remove non-essential personnel from the Reactor Building.
This was the situation of February 11, 1981 when, in fact, a large group of construction personnel were refused entry to the Reactor Building due to the imminent head lift. However it is not a procedure requirement to evacuate the building during head lift because a number of mechanics and support personnel are required to be engaged in the head lift itself.
The activity released on February 11, 1981 was a signi ficant quanti ty of Xe-133 It resulted in local high survey readings by the Health Physics Technicians in attendance and a notification to the Operators and maintenance personnel to leave the Reactor Building.
It caused automatic termination of the Reactor Building purge by a trip function of the Reactor Building gas monitor. Other evidence of high gas activity was the observation of clothing contamination on exiting workers, with the gaseous activity diffusing rapidly.
In spite of the fact that a significant quantity of Xe-133 was discharged, the Emergency Plan was brought into use only to effect a local evacuation,
/N which under the speci fic requi rements of AP.500E-1, does not result in
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R. H. Engelken-December 16,.1981 kj notification of the NRC. There were calculations made.to assure that reinstating the' Reactor Building purge would not result in exceeding the Technical Specification limits. A subsequent study of plant records -and conditions was made to provide the estimate of activity discharged, it is clear that plant personnel were fully aware that the h'ead lift resulted in more gaseous activity than had previously been experienced.
The local activity indications and automatic termination of the Reactor Building purge were rapid actions that gave the proper indications and alerting of the proper personnel. The proper responses were made in accordance with the Emergency Plan and evaluations were made that allowed restart of the. Reactor Building purge and resumption 'of work.
The District does not consider that the event should have been classified as an " accidental, unplanned or uncontrolled radioactive release" since no accident was involved, plans were existant to cope with the operational step and the release was maintained under control.
Pursuant to the.
phrase " Normal or expected releases from maintenance or other operational activitles are not included", it is our position that, although previous releases may have not been experienced at levels that were observed in February, the subject release was in fact normal and expected.
Item B NCR S-1869 was written and dispositioned to procure and install Reactor Building stack and Auxiliary Building stack flow measurement and recording devices. ECN A-2457 has been written to install these systems 6%
and the equipment is on site. The District expects to be in full-compliance with this item by the completion of the next refueling outage.
The radwaste service area fan (EF-A-9) is not in service and will remain out of service unt * ! a new exhaust system for that fan is complete. The new system will have flow measurement and recording capabilities.
A John
. Mattimoe Assistant General Manager and Chief Engineer i
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