ML20086F620
| ML20086F620 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 06/06/1975 |
| From: | Jackie Jones CAROLINA POWER & LIGHT CO. |
| To: | Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| Shared Package | |
| ML20086F617 | List: |
| References | |
| AO-50-261-75-11, NG-75-860, NUDOCS 8401030442 | |
| Download: ML20086F620 (3) | |
Text
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E CP&L Carolina Power & Light Company June 6, 1975 File: NG-3513 (R)
Serial: NG-75-860 Mr. Norman C. Moseley, Director U. S. Nuclear Regulatory Commission Region II, Suite 818 230 Peachtree Street, N. W.
Atlanta, Georgia 30303
Dear Mr. Moseley:
H. B. ROBINSON UNIT NO. 2 LICENSE NO. DPR-23 REACTOR COOLANT SYSTEM OXYGEN CONCENTRATION In accordance with 6.6.2.a of the Technical Specifications for H. B. Robinson Unit No. 2, the attached Abnormal Occurrence Report is sub-mitted for your information. This report fulfills the requirement for a written report within ten days of an Abnormal Occurrence and is in accord-ance with the format set forth in Regulatory Guideline 1.16, Revision 1.
Yours very truly,
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J. A. J s
Executive Vice-President Engineering, Construction & Operation DBW:me Attachment cc: Messrs. N. B. Bessac P. W. Howe J
R. E. Jones D. Knuth /
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[O J. B. McGirt D. B. Waters
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0401030442 750804 PDR ADOCK 05000261 S
PDR 33fi i #!!e vi!" Street. P. O flox 1551. Raleigh N C. 27602
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O ABNORMAL OCCURRENCE 1.
Report No.
50-261/75-11 2a.
Report Date June 5, 1975 2b.
Occurrence Date May 27, 1975 3.
Facility H. B. Robinson Unit No. 2 Hartsville, South Carolina 29550 4.
Identification of Occurrence The Reactor Coolant System (RCS) oxygen concentration was 0.16 PPM with the reactor at power constituting an abnormal occurrence as defined in Technical Specification 1.8.b.
5.
Conditions Prior to Occurrence i
The reactor was operating at 33% power and increasing following a mainte-nance outage.
6.
Description of Occurrence At 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br />, an analysis of the RCS revealed the oxygen concentration to be 0.16 PPM.
This constitutes a violation of Technical Specification 3.1.6.1 which limits RCS oxygen to 0.1 PPM above 250 F.
A sample taken prior to increasing the temperature above 250 F was within the limit of 3
O.1 PPM.
7.
Designation of Apparent Cause of Occurrence CC To scavenge oxygen from the RCS a minimum hydrogen concentration of 15 /kg is required. At 0910 hours0.0105 days <br />0.253 hours <br />0.0015 weeks <br />3.46255e-4 months <br /> the hydrogen concentration was 9 c/kg.
The I
volume control tank (VCT) apparently had a mixture of hydrogen and nitro-gen limiting the amount of hydrogen getting to the RCS.
8.
Analysis of Occurrence The RCS was vented properly and hydrazine was added to scavenge oxygen prior to plant heatup. During plant heatup a hydrogen atmosphere was placed on the VCT to add hydrogen to the RCS and reduce the oxygen con-centration. However, the increase of hydrogen in the RCS was abnormally slow which resulted in a high oxygen concentration.
1 9.
Corrective Action The VCT was vented several titces removing nitrogen and establishing a higher concentration of hydrogen. The RCS hydrogen concentration increased and-at.1115 hours0.0129 days <br />0.31 hours <br />0.00184 weeks <br />4.242575e-4 months <br /> the RCS oxygen concentration was below detectable limits.
10.
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