IR 05000338/1979011
| ML19289E826 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 03/16/1979 |
| From: | Gibson A, Zavadoski R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML19289E801 | List: |
| References | |
| 50-338-79-11, 50-339-79-16, NUDOCS 7905290142 | |
| Download: ML19289E826 (5) | |
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o UNITED STATES
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NUCLEAR REGULATORY COMMISSION ug REGION 11
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101 M ARIETTA STREET,N.W.
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ATLANTA, GEORGIA 30303
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Report Nos.: 50-338/79-11 and 50-339/79-16 Licensee: Virginia Electric and Power Company P. O. Box 26666 Richmond, Virginia 23261 Facility Name: North Anna Units 1 and 2 Docket Nos.:
50-338 and 50-339 License Nos.:
NPF-4 and CPPR-78 Inspection at North Anna Site near Mineral, Virginia 5 f/4 19 8 rid A' t Inspector:
Date Signed R. W. Zavadoski 3f//e[/9 Approved by: /
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h-t A. F. Gibson, Section Chief, FF&MS Branch Da'te Signed SUMMARY Inspection on February 28 - March 2, 1979 Areas Inspected This special unannounced inspection involved 18 inspector hours onsite in the area of release of radioactivity to the Unit 2 storm drain.
Results Of the one area inspected, one apparent item of noncompliance was found.
(Infraction - release of radioactivity to an unrestricted area (338/79-11-01, 339/19-16-01), Paragraph 5).
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DETAILS 1.
Persons Contacted Licensee Employees
- J. D. Kellams, Supervisor of Operations
- E. W. Harrell, Supervisor of Maintenance
- D. M. Hopper, Health Physics Supervisor
- D. L. Smith, Resident QC Engineering Operations
- S. L. Harvey, Operations Supervisor
- J. M. Mosticone, Operations Coordinator Other licensee employees contacted during this inspection included craftmen, technicians, operators, mechanics and office personnel.
NRC Resident Inspector
- M. Kidd
- Attended exit interview.
2.
Exit Interview The inspection scope and findings were summarized on March 2, 1979 with those persons indicated in Paragraph 1 above. The item of noncom-pliance was discussed by telephone with W. R. Cartwright, Station Manager, on March 9, 1979.
Mr.
Cartwright stated that steps had been taken to preclude recurrence of this item.
3.
Licensee Action on Previous Inspection Findings Not inspected.
4.
Unresolved Items Unresolved items were not identified during this inspection.
5.
Radioactivity Release a.
Event Description (1) On the evening of February 27 the Unit 2 volume control tank (VCT) and the Unit 2 charging pumps were operating in a recirculation mode and the safety relief valve on the seal water heat exchanger had been replaced with a spool piece.
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-2-During the period of recirculation, 1840 to 1932 on February 27, 1979, the level of the VCT dropped from 42% to 21% on two occasions. Followup by the licenaee revealed that approximately 1170 gallons had been lost from the volume control system to the Unit 2 reactor vessel by leakage thru a control valve, number 2-CH-249. The Unit 2 reactor vessel was not controlled as a restricted area.
At the time recirculation began, the VCT was at atmospheric pressure. When it dropped from the 42% level to the 21% level, a vacuum was created in the VCT. Concurrent with the loss of 1170 gallons from the Unit 2 VCT, the Unit 2 reactor vessel was being intermittently drained by means of a portable pump to the fuel transfer canal. The fuel transfer canal was draining to the contain-ment sump. The sump was being pumped to a storm drain by means of a pump and fire hose. A liquid sample was taken from the Unit 2 VCT on February 27, 1979. The sample results indicated radioactive xenon, cesium and iodine present.
(2) Licensee representatives estimated that approximately 75 millicuries of radioactivity were released to the Unit 2 reactor vessel during this operation.
Seventy-one millicuries were due to xenon-133 and xenon-135. A licensee representative further estimated that 3.11 millicuries was eventually released te the storm drain system. About 1% of the xenon reached the containment sump; the remainder entered the air in Unit 2 containment and was discharged to the enviror. ment via ventilation exhaust. At the site boundary, the estimated liquid concentration was less than one percent of maximum The pennissible concentrations (MPC) for the mixture.
concentration of radioactive gas at the site boundary was negligible.
Licensee representatives estimated that, at the release point to the Unit 2 containment, the anximum liquid concentration was 310 times MPC for iodine-131, as specified in 10 CFR 20, Appendix B, Table II, Column 2.
No significant exposure of personnel to radiation or radioactive material occurred.
(3) On March 9, 1979, licensee management was informed by telephone that the release of water containing radioactivity in excess of the values specified in 10 CFR 20, Appendix B, Table II, Column 2, to an unrestricted area in Unit 2, was in noncompliance with Effluent Technical Specification 2.2.1.a (338/79-11-01, 339/79-16-01).
b.
Licensee Response (1) After it was realized that the Unit 2 VCT was contaminated, (approximately 3:00 a.m. on February 28, 1979) all liquid 2047 J54
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-3-releases from the Unit 2 containment were terminated, the Unit 2 containment was evacuated, and the following radiological surveys were made:
(a) Air samples for radioactive gases and particulates were takei in containment. Results were well below MPC.
(b) Smears for loose surface radioactive contamination were taken in containment. All werg below the licensee's control value (1000 dpm/100 cm ).
(c) liquid samples were taken from the following systems and components:
(1) Unit 2 refueling water storage tank (2) Primary grade water system (3) Closed cooling water system (4) * Unit 2 sump (5) Unit 2 refueling cavity (6) * Unit 2 fuel transfer canal (7) * Storm drain discharge (8) C boric acid storage tank (9) Safety injection accumulators 2A and 2B (10) Component cooling system (11) * Unit 2 reactor vessel (12) * Unit 2 VCT
Items without asterisks showed no detectable levels of xenon, iodine or cesium.
(d) Radiation surveys conducted in the Unit 2 containment detected no direct radiation greater than Imrem/ hour.
(2) Residual water in the Unit 2 chemical and volume control system and containment sump was transferred to the high level liquid waste system.
The remaining water in the reactor vessel (approximately 6 inches in the bottom of the vessel) was diluted to well below MPC levels by the addition of pure water to the vessel.
(3)
In order to avoid a similar problem in the future, the Unit 2 VCT was flushed and filled with clean water, the boundary valves were identified and tagged.
Licensee representatives stated that the VCT would be s:mpled following any change to the system in order to preclude another release.
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c.
Contamination Pathway From Unit 1
.o Unit 2 (1) The contamication of the Scit 2 VCT was suspected to have come from Unit 1 via a r.oss tie.
On March 1, 1979, licensee representatives found a torn diaphragm on vafve number 1-CE-152.
This valve is the drain valve for the Unit 2 VCT. The piping beyond the valve is interconnected with the drain line from the Unit ! VCT. Both are connected to a high level waste tank header, a contaminated system.
The possibility existeu foc cross contamination via these drain lines if the pressure in the Unit 2 VCT was lower than the pressure in the high level waste tank header and flow restrictioni could be The torn diaphram was replaced on March 1, 1979.
overcome.
(2) On March 12, 1979, licensee representatives identified two defective relief valves in the sampling system. The valves are numbered SS-111 and SS-211. The licensee determined that while taking a samp!e of primary coolant on Unit 1, baciflow thru valve SS-211 would lead to contamination of the Unit 2 VCT. The licensee is evaluating the cause and duration of the leaking relief valves and will submit a thirty day report as required by 20 CFR 20.405 (338/79-11-02, 339/79-16-02).
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