ML19305A590
| ML19305A590 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/21/1977 |
| From: | Herbein J METROPOLITAN EDISON CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| GQL-1769, NUDOCS 7910250835 | |
| Download: ML19305A590 (2) | |
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METROPOLITAN EDISON COMPANY cucerotaarorcineeat custicuritiries canpoiu.ric:.
i POST OFFICE BOX 542 READING, PENNSYLVANI A 196G3 TELEPHONE 215 - 929-3601 Dec e=ber 21, 1977 GQL 1769 Mr. Boyce H. Grier, Director Office of Inspection and Enforcement, Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19h06
Dear Sir:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Docket No. 50-289 Operating License No. DPR-50 IE Bulletin No. 77-04 In response to IE Bulletin No. T7-04, cc teerning pH control of the containment sump, Metropolitan Edison Company has re rieved the TMI-l FSAR and Technical Specifications and Standard Review Plans (SRP) Section 6.1.3 and Section 6.5.2.
The TMI-1 Buildin 3 pray System utilizes the Borated Water Storage Tank (BWST),
the Sodium Thiosulfate Tank (STI), and the Sodium Hydroxide Tank (SHT). The Sodium Thiosulfate is used for radioiodine absorption and is most stable at a pH of 9 5 The Sodium Hydroxide is used to raise the pH to approximately 9 5 Calculations have been made, assuming a minimus BWST level and maximus STT and SHT level, and assuming a mari m m BWST level and minimum S'I'P and SHT levels.
The former case results in an initial pH of 9.8 and the latter case results in an initial pH of 91. Also included in these calculations were variations in the boron concentrations of up to 70 ppm boron.
Following the LOCA, the pH of the containment sump vill very slowly decrease due to the decompositien and reaction of thiosulfate. However, as noted in Section 9 2.1.2 of the TMI-1 FSAR, following a LOCA sodium hydroxide from the unit's sodium hydroxide storage tank can be transferred into the suction line of either of the two decay heat pumps for control of the pH of the circulating reactor building sump fluid.
Although SRP Section 6.1.3 indicates an optimum pH between 7 and 8, it should be noted that a later SRP (SRP Section 6.5.2) indicates that the equilibrium cump pH should be above 8.5 for sodium hydroxide and sodium thiosulfate sprays.
79/0256P3s'
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2-Decembrr 21, 1977 Mr.*Boyca H. Gricr, Dirse,r GQL 1769
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i B: sed on the above, Met-Ed is confident that the system design specifications as described in the TMI-1 FSAR will be met for all operating conditions permitted by the Technical Specifications, as applicable to the containment cump water sources.
Sincerel
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J. G. Herbein Vice President JGH:RJS:gs cc:
C. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Division of Reactor Operations Inspection Washington, D.C.
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