ML20084L036
| ML20084L036 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 06/19/1974 |
| From: | Kalivianakis N COMMONWEALTH EDISON CO. |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084L039 | List: |
| References | |
| NJK-74-124, NUDOCS 8305200147 | |
| Download: ML20084L036 (2) | |
Text
-3 Commr
'zith Edison
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/g Mr. John F. O ' Leary, Di rector Directorate of Licensing Regulation U. S. Atomic Energy Commission Washington, D. C.
20545
Reference:
Quad-Cities Nuclear Power Station Unit 2 Docket No. 50-265, DPR-30, Appendix A, Sections 1.0.A.2, 3.6.C.4, and 6.6.B.l.a
Dear Mr. O ' Leary:
The purpose of this letter is to inform you of the details concerning high con-ductivity in Unit 2 reactor water on June 9,1974 This abnormal occurrence was previously reported to Region ill, Directorate of Regulatory Operations by tele-phone and telegram on June 9.1974, and to you by telegram on June 10, 1974.
PROBLEM AND INVESTIGATION At approximately 5:40 a.m. on June 9,1974, with Unit 2 operating steady state at 645 MWe, the cleanup system was returned to service following maintenance on the 2-1201-30 M0 valve and on the 2-1201-61A pump discharge valve. O f f gas ficw increased from 105 cfm to 220 cfm and settled at 150 cfm within 10 minutes. The of f gas radiation monitors increased from 1000 units to 2100 units and subsequently dropped to 1200 units within 20 minutes. The main chimney radiation rnonitors in-creased from 300 cps to 500 cps and then decreased to 400 cps within 25 minutes.
Reactor water conductivity increased to greater than 10 m.hos /cm, thus exceeding Technical 5pecification 3.6.C.4.
Subsequent sampling showed a maximum conductivity of 40.5 pmbos/cm at 11:20 a.m. on June 9,1974.
EVALUATION AND CORRECTIVE ACTION CAUSE Af ter completion of naintenance on the cleanup system, the system was filled with water and vented. When the system was returned to service, an air pocket was apparently released to the reactor and subsequently reached the hotwell. Probable formation of carbonic and nitric acids from the introduction of air into the reactor water system caused the reactor water pH to be reduced to 3.9 This low pH allowed corrosion products to co into solution, causing additional increase in conductivity. Analysis of rcactor vater showed primarily Mn-56 with normai radio-iodine and chloride concentrations.
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