ML19329A686
| ML19329A686 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 08/05/1977 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19329A681 | List: |
| References | |
| RO-287-77-09, RO-287-77-9, NUDOCS 8001090671 | |
| Download: ML19329A686 (1) | |
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l'8 DUKE POWER COMPANY OCONEE UNIT 3 Report No.: RO-287/77-9 Report Date: August 5, 1977 Occurrence Date: July 7, 1977 Facility:
Oconee Unit 3, Seneca, South Carolina Identification of Occurrence: High chloride concentration in reactor coolant system Conditions Prior to Occurrence. Unit at 100 percent full power Description of Occurrence:
On July 6,1977 at 1000, a routine chemical sample indicated a chloride con-centration of 0.22 ppm in the Oconee 3 reactor coolant system. Pursuant to Technical Specification 3.1.5.2, corrective action was initiated within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to reduce the concentration by placing the "A" deborating demineralizer in service. However, due to this demineralizer having a high boron concen-tration, only intermittent operation of the demineralizer was possible.
The maximum chloride concentration reached was 0.26 ppm. At 0930, July 7, 1977, a reactor shutdown was initiated in accordance with the requirements of Technical Specification 3.1.5.4.
At this time, the chloride concentration in the reactor coolant system was 0.17 ppm and decreasing.
At 1350, the concentration was 0.14 and the reactor shutdown was terminated.
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~ Designation of Apparent Cause of Occurrence:
The apparent cause of this occurrence was the general degradation of the two purification demineral1zers due to extended use.
Sluicing of these demineralizers was not possible due to excessive inventories of liquid 3
waste from recent Oconee outages.
A alysis of Occurreu e:
The Oconee Technical toecification limits on chloride concentration in the reactor coolant system are conservative margins which assure that stress corrosion attack does not occur. A 24-hour time period for action to
. correct the high concentration is allowed by Oconee Technical Specification 3.1.5.4, then'a hot shutdown is required. All technical specification requirements were followed during this incident resulting in reactor coolant system protection and operating flexibility. The combination of time, temperature and pressure and chloride concentration have been evaluated Land it is concluded that sufficient protection from stress corrosion attack existed during this incident.
It is concluded that the health and safety of the_public were not affected by this incident.
Corrective Action:
4 Both purification demineralizers have been replaced with fresh resins.
This should prevent recurrence of this incident in the future.
8001090fy
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