L-77-103, Response to Request for Additional Information Re Overpressure Protection
| ML18227D276 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 03/31/1977 |
| From: | Pearson J, Robert E. Uhrig Florida Power & Light Co |
| To: | Lear G Office of Nuclear Reactor Regulation |
| References | |
| L-77-103 | |
| Download: ML18227D276 (9) | |
Text
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Florida Power 8 Light Company liiami, Florida Robert E. Uhrig II)I7l) I I'li, I l.i)C'SVaI.
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Ltr. re our 2/9/77 ltr. and their 12/1G/76 ltr...trans the following:
>CKNowL@DG DG NOT REMGyp Consists of reouestec additional information concerning overpressure protection.....
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FLORIDA POWER 5 LIGHT COMPANY March 31, 1977 L-77-103 K~TM>Waerl<<@pg Office of Nuclear Reactor Regulation Attention:
Mr. George Lear, Chief Operating Reactors Branch 53 Division of Operating Reactors U. S. Nuclear Regulatory Commission Washington, D. C.
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Dear Mr. Lear:
Re:
Turkey Point Units 3 and 4
Docket Nos.
50-250 and 50-251
~Over ressnre Protection Your letter of February 9,
1977 requested additional information concerning our December 10, 1976 submittal on overpressure protection.
A reply to your request, numbered to correspond to your questions, is attached.
Very truly yours,
.~C-vY)V(')3 4 Robert E. Uhrig Vice President REU/MAS/cpc Attachment cc:
Mr. Norman C. Moseley, Region II Robert Lowenstein, Esquire
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PEOPLE... SERVING PEOPLE
ATTACHMENT A Re:
Turkey Point Units 3
& 4 Docket Nos.
50-250
& 50-251 Over ressure Protection I.
FPL Over ressure Miti atin S stem Desi n Features Our letter of March 1, 1977 (L-77-74) described in detail the FPL proposed "Overpressure Mitigating System".
This system is based on the "Reference Mitigating System" described in our letter of December 10, 1976 (L-76-422) with certain design features added to be responsive to the NRC design criteria.
All items of concern listed in para-graphs a through g of the February 9
NRC letter were addressed in the March 1 FPL letter.
II.
Additional Information 1.
Refer to Sections 6.0 and 9.0 of the Turkey Point Units 3 and 4
FSAR for piping and instrumentation diagrams and for modes of system operation during solid plant conditions.
Refer to Item 3 in the attachment to our March 16, 1977 letter (L-77-81) for additional information.
2.
The Overpressure Mitigating System is not a safety
- system, therefore, a failure modes and effects analysis should not be required.
However, to facilitate your review of our proposed
- system, we have evaluated the effects of single failures on the ability of the proposed system to perform its pressure relieving function.
The results of that evaluation are presented in Attachment B.
3.
Initial conditions for the analysis of the pressure transient will be described in a generic report on analytical assumptions,
- models, and results.
FJe expect. to be able to submit this report in May, 1977.
4.
Computer codes used to model the overpressure transients will be described in the generic report planned for May, 1977.
5.
Relief valve backpressure considerations will be discussed in the generic report planned for May, 1977.
6.
Refer to Item 6 in the attachment to our March 16, 1977 letter (L-77-81) for a discussion of RHR relief capability.
7.
a.
The pressurizer power-operated relief valves have open/shut indication on the main control board.
ATTACHMENT A PAGE 2
II.
Additional Information (Continued) 7.
(Continued) b.
The pressurizer safety valves and the power-operated relief valves discharge to the pressurizer relief tank.
This tank has level, temperature, and pressure indication on the main control board.
In addition, these three signals have a common alarm, also on the main control board.
Any lifting of a relief or safety valve will be seen in the pressurizer relief tank immediately.
c.
The residual heat removal relief valves discharge to the pressurizer relief tank.
8.
Refer to Item 3 in the attachment to our March 16, 1977 letter (L-77-81) for a discussion of administrative control of certain valve motor operators.
In general, when power is removed from a valve motor operator, the indication of valve position 'is no longer present.
Power is removed from a valve motor operator by opening the breaker at the motor control center.
ATTACHMENT B Re:
Turkey Point Units 3
a 4
Docket Nos.
50-250 6 50-251 Over ressure Protection SINGLE FAILURE ANALYSIS Resultant Effect on 0 erabilit Failure Mode PORV 1
PORV 2
Comment Loss of channel 1 instrument, power Loss of channel 2 instrument power Loss of PORV 1 battery Loss of PORV 2 battery Loss of instrument air Loss of off-site power Loss of off-site power plus loss of either diesel Not Op Op Not Op Op OP Op Op Op Not Op Op Not Op OP Op Op Note 1 Note 1
Note 2
Note 1
Loss of letdown Isolation of RHR Closure of PORV 1 isolation valve Op Op Not Op Op Op Op Note 2
Note 2
Closure of PORV 2 isolation valve Op Not. Op Inadvertent SI Manual starting of SIS pump Op Op Op Op Note 2
Note 2
ATTACHMENT B PAGE 2
Resultant Effect on Operability Failure Node PORV 1
PORV 2
Comment Manual starting of additional charging pump Op Op Note 2
Manual starting RCP Op OP Note 2
Failure to activate low pressure setpoint channel 1
Failure to activate low pressure setpoint channel 2
Not Op Op Op Not. Op Note 3
Note 3
Problems with operation of pressurizer relief tank Op Op NOTES
- Not Op denotes that this valve is not operable and not capable of performing its pressure relieving function.
Op denotes that this valve is operable and can perform its pressure relieving function.
Note 1
The power for each channel is supplied from an inverter on a station battery.
Note 2
For all possible causes of overpressurization, no failure of PORU 1 or 2 results.
Note 3
Alarm will alert the operator to this condition.