ML20085M913
| ML20085M913 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 01/04/1974 |
| From: | Gilleland J TENNESSEE VALLEY AUTHORITY |
| To: | Kruesi F US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20085M910 | List: |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8311090457 | |
| Download: ML20085M913 (2) | |
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g ENNESSEE VALLEY ALTTHORITY CHATTANOOGA, TENNESSEE 37401 40
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Jnnuary 4,
l'Ph ANNIVE ASA AY OF PEOPLE IN 4
PA ATNE ASHIP
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Mr.
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Kruesi, Director Directorate of Regulatory Operations s
U.S. Atomic Energy Commission I
Washington, DC 20545 11.4 I
Dear Mr. Kruesi:
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In conformance with paragraph 50.55(e) of 10 CFR 50, this is submitted as a final report on a design deficiency in the control
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logic of HPCI and RCIC systems of our Browns Ferry Nuclear Plant 7
units 2 and 3.
Initial report of this deficiency was made to
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AEC-DRO Region 11 on November 10, 1973, and interim reports were submitted to your office on December 10 and December 14.
5a Correc t ive ac tions to be taken on units 2 and 3 involve removal
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E of the HPCI and RCIC high reactor water level trips that currently 1.
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originate in the Feedwater Control System, and the installation of M
four additional qualified high reactor water level switches.
These IYy_ -l..,A g
i new switches, with the four existing switches, will be arranged in
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g redundant piping manifolds such that the HPCI and RCIC will each
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have four switches (two in each manifold) of which two are powered
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from the Division 1 250-volt d.c.
supply and two from the Divisioe 11
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f 2 50-vo l t d.c.
supply.
The four switches for each turbine will
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L energir.e a logic circuit that will trip the machine when either two k - #
of the existing switches or two of the new switches are closed by gi high reactor water level. Units 2 and 3 will have these modifications
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made before fuel loading.
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of the relays in the tripping logic so that they had to be energized
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L to trip, eliminating the lockout feature so that manual reset of the
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Mr. F. E. Krucsi January 4, 1974 l
tripping logic would not be required, and changing the power supply for one channel to a 250-volt d.c. supply through an inverter (see TVA abnormal occurrence report BFAO-7334W, November 19, 1973, E. F.
Thomas to John F. O' Leary). The corrective actions described above for units 2 and 3 have since been applied to unit 1.
Very truly yours, J. E. Gilleland Assistant to the Manager of Power CC:
Mr. Norman C. Moseley, Director Directorate of Regulatory Operations U.S. Atomic Energy Commission Region II - Suite 818
'230 Peachtree Street, NW.
Atlanta, Georgia 30303 J
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