ML19323B857
| ML19323B857 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain, Crane  |
| Issue date: | 03/08/1978 |
| From: | Higginbotham L, Thornburg H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Volgenau E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| TASK-TF, TASK-TMR NUDOCS 8005140352 | |
| Download: ML19323B857 (5) | |
Text
DISTRIBUTION:
8005140353
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MER7RANDG4 FOR:
E. Volgenau, Director
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Office of Inspection and Enforcement r '_
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Harold D. Thornburg, Director I-Division of Reactor Operations Inspection IE
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Leo B. Higginbotham, Acting Director
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Division of Fuel Facilities and Materials
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Safety Inspection, IE
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SUBJECT:
RESULTSOFFORhST.YRAININVESTIGATION
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A tw phase investigation of an event that occurred at the Fort St..
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Vrain facility on January 23, 1978, was conducted by the NRC Region-3 IV (Dallas) office. The first phase of the investigation (January 23-
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26,1978) dealt with identification of the cause of the event, the
-l consequences of the event, licensee response to the event, and ressonse by federal, state and local authorit 3.s (IE Investigation Peport No. 50-267/78-03). The second phase of the investigation
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(February 6-10, 1978) dealt with an allegation that the event was
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intentionally caused by a person or persons tampering with certain centrols and instranentation (IE Investigation Report No. 50-267/78-04).
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REASON FOR NRC INVESTIGATIOR Dmugh the consequences of the event were minimal, conduct of an in-depth investigation was deemed appropr.iate for the following reasons:
1.
The NRC Incident Response Center was activated in response to 3
licensee notification that a significant off-site radioactive
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release had occurred. Consistent with the long standing NRC policy of conducting prompt on-site followup subsequent to
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significant events, it was determined that an investigation y
should be conducted to determine the cause of the release o
and assess the personnel and plant safety status.
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2.
Site evacuation calling for coordination of licensee, federal, M,7 i
state and local government response was effected. It was b=
decided that the effectiveness of such an evacuation should ff./
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be evaluated so that weaknesses, if any, could be delineated r,p,0T g.';3l :
and subsequently corrected.
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NRC Form 318 l2 76) NRCM C2040 e u.s. oovsmuurwr pniwrimo orricre 1,7s.ese-7ea I~
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3.
There was an allegation that the avent was intentionally caused by plant personnel.
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There was considerable public interest in the event.
SIMMRY i
The initiating causa of the January 23 event was determined to be a malfunction of the water level controller for the Loop 2 Bearing Water l
Surge Tank. This malfunction initiated a series of equipment inter-(fourcuries)of actions leading to the release of a small quantity (helits).
i fission products contained in the primary coolant The l
j consequences of the release were minieel. The licensee implecented i
its esiergency pl,an. Although the objectives of the emergency plan were achieved, some minor problems were identified. The NRC has taken action to assure that power operation will not resume at Fort St. Vrain until identif!ed problems have been corrected. The investigation established that the event was not intentionally caused.
CETAILS Cause of Event Failure of the primary water level controller for the Loop 2 Bearing Water Surge Tank was identified as the initiating cause of the event.
An investigation of allegations that the event might have been the result of tampering by a person or persons established that the eve =tt 1
was not intentionally caused by such tagering. This conclusion is based on the following facts:
1.
Examination of the controller by NRC inspectors and the licensee I
disclosed no evidence of tampering.
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2.
Design review of the controller by MRC personnel revealed that a covert means of causing delayed failure of the level controller was not probable. IE:HQ specialists and highly competent field inspectors considend the matter at length, and concluded that if tampering with the controller had in.wi. d. the effects would have been observed within a matter of seconds following the W ing.
3.
IfRC intentews of two mechanical craftsmen working near the l
controller revealed that:
a.
They observed no one tampering with the controller Defore or dur1ng *:he event.
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b.
The did at disturb or tamper with the contmilea.
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NRC Form 318 (2 76) NRCM 02040 c u.s. oo v ERNMENT P RIN TING o P PIC Et 1976 434_702
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The two workers were eriployed by contractor and did T
rot have the background and familiarity with instrurenta-tion to have intentionally initiated the resulting sequence
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of events.
4.
The alleger did not have evidence that intentional tampering had occurred. During discussions with the investigators, the alleger
=l stated that he was concerned that the possibility of sabotage would be overlooked by the NRC during its review of the event. He did not mean to imply that he had proof the event was an act of TM sabotage.
Impact on the Public
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The radiological consequences of the event with respect to the impact on the pubite and the environs was naaligible. Approximately 4 curies of noble gases and 5 microcuries of iMI were released during the
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event. This anount of radioactivity would have caused approximtely
.1 millirem (3-4 times that from natural background radiation level in Colorado) whole body exposure to a person located at the site boundary during the course of the event.
Inoact on Plant Personnel Exposure of plant personnel as detemined by personnel dosimeters was lir~ted to approximately 10 mrem. Whole body counts, urine samples ant thyroid surveys of representative plant personnel revealed that no internal contamination resulted from the event.
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Response by the t.icensee
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When confronted by an indicated elevated release of radio-iodine, licensee management at the site activated the facility emergency plan.
Given the existing circumstances, the ifcensee's response to the event was conservative. The licensee apparently predicated 'iis actions on the randout free the iodine monitor in the plant stack. Since the iodine monitor was actually detecting energy fmm radionuclides other than iodine, fts reading resulted in the high initial estisate of radioactive release.
Criticism of the licensee in this regard must be aimed only at his need
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for better evaluation of available technical data. Such criticism should not in any way detract from the NRC desire that licensees respond
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to protect the public in similar situations.
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l NRC Form 318 ( 761 NRCM hk o u.s. Cow s Nbs[N T PEIN T NO O F E 197s.e34 7 3 i
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Implementation of the emergency plan was found to be essentially as designed. Evacuation of non-essential plant personnel to the primary assenbly poiot (Visitor's Center) was abandoned because of wind direction. Evacuees moved to the secondary asseebly point where facilities were sore crowded and comunications equipment was limited.
Tnis relocation caused some confusion but it did not significantly impact overall emergency response. The licensee was late with some of his notifications and initially did not supply sufficient informa-tion (category of incident and areas affected).
It does not appear that these lapses were intentional; however. It did impact on the response of state and local agencies.
Responses by Government Agencies L'hile there were some minor difficulties in coordination of the response activities of the federal, state and local authorities each performed its intended function in a timely fashion and the objectives of their respective emergency plans were achieved.
Enforcement Action
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The investigation revealed that the licensee was in noncoc:pliance (infractions) with license requirements in the following areas:
i 1.
Provisions of the emergency plan regarding timing and content of notifications.
2.
The radioactGaty release rate during the event exceeded the allowable release rate by a factor of approximately 3.7.
3.
The surveillance program associated with the Helium Circulator Auxiliary Systen was not fully implemented.
Regional Office Notices of Violation have been issued to the licensee on these satters.
Technical Matters Requiring Cei. J ve Action The investigation disclosed scan specific technical matters which have been identified for action by the licensee prior to resumption of power operations.
1.
The event could probably have been terminated prior to
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release of fission products if the helium dryers could
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have been isolated frem the control room. Provision for
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_ _,i NRC Form 31812 76) NRCM O2040 c u.s. oo v ERNMEN T W RIN TIN G OF FIC E: 1976_S34-732 1
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d A need for an improved failure mode and effects analysis for
=H the heltua circulator auxiliaries was identified and will be j
coc:pleted by the licensee.
1 3.
Inadequacies in the surveillance program for the Helium Circulator Auxiliary System were identified. The surveillance program will be revised by the licensee and reviewed by the NRC staff.
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The surge tank level controller that failed has been replaced.
All four surge tank level controllers have been functionally
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tested.
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All damage resulting from the event has been repaired.
5 Harold D. Thornburg, Director Division of Reactor Operations
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Inspection. I
/ 5 Leo B. Higginbotham Acting Director Division of Fuel Facilities and Materials Safety Inspection. IE Enclesures:
1 Investigation Report 50-267R8-03 2
Investigation Report 50-257RB-04
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