IR 05000338/1978034
| ML19274D123 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 11/27/1978 |
| From: | Gibson A, Jenkins G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML19274D114 | List: |
| References | |
| 50-338-78-34, 50-339-78-34, NUDOCS 7901120177 | |
| Download: ML19274D123 (7) | |
Text
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UNITED STATES
[p* 88Guq(o, NUCLEAR REGULATORY COMMISSION
[
REGION 11
' 3; 101 M ARIETTA sTRE ET, N.W.
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' r ATL ANT A, GEORGIA 30303 o
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Report Nos.-
50-338/78-34 and 50-339/78-34 Docket Nos..
50-338 and 50-339 License Nos.: NPF-4 and CPPR-78 Licensee: Virginia Electric and Pet:cr Company P. O. Box 26666 Richmond, Virginia 23261 Facility Name: North Anna i and 2 Inspection at:
North Anna Site Inspection conducted:
October 30 - November 3, 1978 Inspector:
G. R. Jenkins Reviewed by:
A,
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II A. F. Gibson, Chief Date Radiation Support Section Fuel Facility and Materials Safety Branch Inspection Summary Inspection on October 30 - November 3, 1978 (Report Nos. 50-338/78-34 and 50-339/78-30)
Areas Inspected:
Routine, unannount ed inspection of radiological aspects of reactor coolant leaks in auxiliary building, followup on Licensee Event Report, and Unit 2 radiation protection preparations.
The inspection involved about 29 inspector-hours on site by one NRC inspector.
Results:
Of three areas inspected, no items of noncompliance were identified.
One deviation was identified (Deviation: Failure to periodically check and replace, respectively, particulate and charecal filters in ev>tainment air monitor (338/78-34-01) pat agraph 7).
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790112 o F77
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RII Rpt. Nos. 50-338/7.8-34 and 50-339/78-34 I-1 DETAILS I Prepared by:
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G. R. Jenkins, Radiation Specialist Date let Radiation Support Section s
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Fuel Facility and Materials Safety Branch Dates of Inspec 'on: 0 t7 e 30 - November 3, 1978 b
fl5 Reviewed by:
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A. F. Gibson, Chief Date Radiation Support Section Fuel Facility and Materials Safety Branch 1.
Individuals Contacted
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- J. D. Kellams, Superintendent, Station Operations
- D. M. Hopper, Health Physics Supervisor
- E. R. Smith, Engineering Services Supervisor
- R. F. Queener, Health Physicist A. H. Stafford, Senior Health Physics Technician C. D Bradley, Senior Health Physics Technician J. D. Gilbert, Health Physics Technician S. L. Harvey, Reactor Shift Supervisor J. M. Mosticone, Reactor Shift Supervisor
_C. T. Phythian, Assistant Shift Supervisor
- D. C. Woods, NRC Coordinator F. Termine11a, Associate Engineer
- Denotes those present at exit interview.
2.
Licensee Action on Previous Inspection Findings (Open) Unresolved Item (78-14-04): Excessive radiation levels in containment.
VEPCO provided additional information on this item by letter to RII dated Se >tember 29, 1978.
This item remains open.
(Details I, paragraph 4)
3.
Unresolved Items
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No new unresolved items were identified during this inspection.
4.
Containment Radiation Levels (78-14-04)
Vepco's letter of September 29, 1978, stated that a final shield design was anticipated to be available by the end of October, 1978, and that implementation of the design would be no later than the first refueling
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RII Rpt. Nos. 50+338/78-34 and 50-339/78-34 I-2 (Unit 1) assuming the design is acceptable. During this inspection, licensee management stated that the final design was not yet complete, and estimated that the design would be received by Vepco from Stone and Webster about November 15, 1978. The various stages of review and approval of the design by Vepco and NRC were discussed. The inspector noted that, in view of this lengthy process, continuing management attention would be required to ensure that the modification was accomplished no later than the first refueling outage.
Licensee management acknowledged the inspector's comments. Licensee management representatives also stated that shielding for Unit 2 is included in the design package, and that Vepco intends t.o complete that modification prior to Unit 2 startup.
5.
Radiclogical Aspects of Reactor Coolant Spills a.
On October 24, 1978, about 1,000 gallons of reactor coolant from the chemical and volume control system (CVCS) was spilled onto the floor of the aaxiliary building basement.
The spill occurred because CVCS water was restored to the alternate reactor coolant system charging header, af ter maintenance, without closing a vent valve and a drain valve. After about 15 minutes, the leak was secured by closing the two valves, and personnel were evacuated from the auxilia ry building.
All evacuated personnel were surveyed. Contamination was detected on the head and/or clothing of 13 persons, primarily due to adsorption of rubidium -88 which has a 17.8 minute half-life.
All contaminated p.rsonnel were decontaminated to levels less than 200 disintegrations per minute.
Contaminated clothing was confiscated, held for radioactive decay, and returned except for c'9 thing of two operators who had been directly sprayed wiin ?;e radioactive water; their clothing was permanently confiscated. Nasal swabs were taken on all persons with head contamination, but oc activity was detected. Whole body counts were obtained on four operators, including the person with the highest initial head contamination of 200,000 disintegrations per minute, and one contractor QC inspector. All results were 10% or less of a maximum permissible organ burden. Air samples for iodine,* particulate, and gaseous activity were collected in the auxiliaty building near the spill area within about one hour of the start of the spill. Rubidium-88 was the only isotope identified above the maximum permissible concentration (MPC) levels specified in 10 CFR 20, Appendix B.
The conce.,tration of Rb-88 identified was about 120 times the MPC value; however, this isotope is treated as an external exposure source in accordance with 10 CFR 20. No external exposure limits were exceeded, or approached, by personnel in the auxiliary suilding during this inciden.
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RII Rpt. Nos. 50-338/78-34 and 50-339/78-34 1-3 b.
The water spilled in the auxiliary building went through floor drains to the building sump, and was pumped to the liquid radwaste processing system.
Airborne radioactivity resulting from the spill passed through particulate and charcoal filters prior to being wleased to the atmosphere through the "A" ventilation vent. Although no ventilation vent gas sample was collected soon after the spill, noble gases released to the atmosphere were evaluated based on applying conservative flow values *o the gas concentrations determined from local samples taken inside the auxiliary building.
Based on this method, the release was
, estimated to be 0.36% of the average quarterly release rate permitted by Technical Specification 2.2.3.b.(1).
Due to
' filtration, no significant iodine or particulate activity was released to the atmosphere; this was confirmed by analysis of the routine weekly ventilation vent samples collected on October 31, 1978.
In addition to detailed discussions with licensee representatives c.
concerning this incident, the inspector resiewed personnel contamination records, whole body count reeults, air sample results, and area contamination survey records. No noncompliance items or deviations were identified in connection with the radiological aspects of the event.
The inspector noted weaknesses in the areas of ventilation vent sampling, nasal swab and whole body count documentation, and communications within the
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health physics group. The inspector's comments were ackno ledged by the Health Physics Supervisor.
d.
On November 2, 1978, a second spill occurred as a result of the apparent failure of a diaphram in the gas stripper associated sith the boron recovery system. The inspector was present when health physics personnel received word that water was leaking from the gas stripper room and running down the wall to the basement level.
Based on the fact that the ventilation vent gaseous radiation monitor alarmed and a frisker on the 259' level went off-scale, personnel.were evacuated f rom the auxiliary building. The leak was secured within about 20 minutes. All evacuated personnel were surveyed.
Low-level facial contamination was detected on one individual; after decontamination no activity was detectable. A nasal swab was taken and revealed no activity.
e.
Air samples for iodine, particulate, and gaseous activity were collected in the auxiliary building outside the gas stripper room at about the time the leak was secured. Constituents identified above maximum permissible concentrations (MPC) were xenon-l?3 (47
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RII Rpt. Nos. 50-338/78-34 and 50-339/78-34 I-4 times MPC) and xenon-135 (10 times MPC). These gases are treated as an external exposure source in accordance with 10 CFR 20.
No measureable external radiation exposure was apparently received by personnel in the auxiliary building due to exposure to these noble gases.
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Air samples from "A" ventilation vent were collected at about thg time the leak was secured. Only xenon-133 was detected (1.4x10 pCi/cc). The licensee calculated that this represented 1.06% of the average quarterly release rate pe rmitted by Technical Specification 2.2.3.b.(1).
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The inspector had no adverse comments concerning the health physics actions associated with this event.
6.
Auxiliary Building Gas Leaks Licansee representatives said that waste gas leakage had been experienced inside the auxiliary building since about mid-October.
Discussions with licensee representatives and review of air sample results indicated that the significant isotopes involved were xenon-133, xenon-135, and rubidium-88; quantitatively, the concentrations ranged from a few percent to 3 times MFC levels. As permitted by 10 CFR 20, the licensee treats these isotopes as an external radiation source.
Several cases of personnel clothing contamination have resulted due to the apparent tendancy of these isotopes, particularly Rb-88, to adhere to clothing.
Licensee management stated that efforts to locate and stop the leaks were being made, and that a design change would probably be required to fully resolve the problem. The inspector stated that this matter would be reviewed further during a future inspection (338/78-34-02).
7.
Licensee Event Followup Licensee Event Report (LER) No. 78-063/03L-0, August 21, 1978, described a failure of the containment particulate and gas radiation monitors on July 28, 1978, due to clogging of both the particulate tad charcoal filters.
The report stated that present procedure was to change the particulate filter on RM-RMS-159 whenever the filter runs out, and that the charcoal filter for RM-RMS-160 was normally changed only when there was low flow through the sample line.
Corrective action stated in the report was that the particulate filter would be checked periodically to verify that it is operating properly, and that the charcoal filter would be changed periodically. On November 2, 1976, an inspector questioned operating personnel who said that no
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RII Rpt. Nos. 50-338/78-34 and 50-339/78-34 I-5 periodic checks or replacement of filters had been instituted af ter this event. The station engineer who prepared the LER said that a
design change to install a plastic window in the filter housing for observation was prepared in early September, but was still under review by station engineering.
The inspector identified the failure to implement periodic checks of the particulate filter and periodic changes of the charcoal filter as a deviation from the licensee'
written committment (338/78-34-01).
Licensee management stated that the breakdown in communications would be investigated and that prompt action would be taken on the design change. The inspector also noted that other station monitors use similar filter systems that should be consi.dered for periodic checks. Licensee management acknowledged the inspector's comment.
8.
Tour of Unit 2 Containment Building An inspector toured the Unit 2 containment building with the Health Physics Supervisor on November 1,1978, observing and discussing the following potential health physics problem areas:
a.
The location of the containment instrument air compressors have been a point of concern in Unit I due to high radiation levels during reactor operation.
The compressors are in a different location in Unit 2 which appears to be better shielded. At the exit interview, management representatives said that the Unit 2 compressors will be relocated to the safeguards area prior to startup, and that the same modification will be made on Unit 1.
b.
The access hatch leading to the Unit 2 in-core probe tubes will be locked and administratively controlled prior to reactor operation, according to the Health Physics Supervisor.
c.
The shiel6ing gap over the Unit 2 fuel transfer tube at the containment wall appears to be identical with that found in Unit 1.
Corrective actions to be taken will depend upon results of surveys scheduled for Unit I during the initial transfer of fuel.
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9.
Health Physics Procedures For Unit 2 Operation The Health Phyr.ics Supervisor said that some additions to existing health physics procedures will be made prior to startup of Unit 2, such as routine survey locations.
No changes in health physics program policies or survey frequencies are anticipate.
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RII Rpt. Nos. 50-338'/78-34 and 50-339/78-34 I-6 10.
Exit Interview The inspector met with management representatives (denoted in on November 3, 1978, and suma rized the scope and paragraph 1)
findings of the inspection.
Items discussed included the deviation discussed in this report.
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