L-81-163, Comments on NUREG-0737 post-TMI Requirements for Containment Pressure Setpoint.Decoupling of Setpoint & Expense of Replacing Instrumentation Not Justified by Any Corresponding Increase in Protection of Health & Safety of Public
| ML17209A949 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 04/09/1981 |
| From: | Robert E. Uhrig FLORIDA POWER & LIGHT CO. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.E.4.2, TASK-TM L-81-163, NUDOCS 8104160189 | |
| Download: ML17209A949 (6) | |
Text
REGUL~JRY INFORMATION DISTRIBUTOR/ SYSTEM (RIDS)
ACCESSION NHR: 8104160189 DOC. DATE: 81/04/09 NOTARIZED:
NO FACIL'.50-335 St ~ Lucie Plant~
Unit. 1~ Florida Power 8 Light'o, AUTH,NAME AUTHOR AFF ILIATION UHRIGg R,E ~
Florida Power 8 Light Co, RECIP ~ NAME; RECIPIENT AFFILIATION EISENHUT,DE G ~
Division of Licensing DOCKET' 05000335
SUBJECT:
Comments on NUREG-0737 post-TMI requirements for pressure setpoint.Decoupling of setpoint 3 expens replacing instrumentation not Justified by any Co increase to protection of health 8 safety of publ DISTRIBUTIDN CODE:
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ENCL 0 TITLE: Response to NUREG -0737/NUREG 0660 TMI Action Plan NOTES:
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FLORIDA POWER IL LIGHTCOMPANY April 9',
1981
'.L-81-163 Director of Nuclear Reactor Regulation Attention:
Mr. Darrell G. Eisenhut, Director Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C.
20555 S
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APR35 198)~
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Dear Mr. Eisenhut:
Re:
St. Lucie Unit 1
Docket No. 50-335 Post-TMI Re uirements C
NUREG 0737 contained Item II.E.4.2.5, Containment Pressure Setpoint.
In our response to NUREG 0737, we committed to review the minimum containment pressure setpoint for containment isolation (CIS) and propose modifications, if any were required.
This letter documents our review and conclusions.
The containment pressure history was reviewed and it was determined that the maximum normal operating pressure would be 2.0 psig.
The containment isolation signal is generated by pressure transmitters PT-07-2A, 2B, 2C, and 2D (Fisher and Porter Model 50 EN 1071).
These transmitters are wide range (0 to 50 psig) and have a total instrument error of 1.6 psig.
Four Bistable Modules (Consolidated Control Model 6N88-1; Instrument numbers BA-103, 203,
- 303, and 403) receive a 4 to 20 MA DC signal from the transmitters which have been conditioned to 1-5 VDC to drive the Bistables.
The Bistable output range is 0.5 to 5.0 VDC, and their setpoint is 5 psig which corresponds to 8.3g of the total output range.
The four Bistables are combined in a two out of four logic that initiates containment isolation actuation.
The allowance to account for Bistable tolerances plus a certain margin to preclude inadvertant containment isolation is 1.4 psig.
The total of operating expected containment pressure and instrument tolerance and error yield a setpoint equal to the existing setpoint of 5 psig.
Any reduction in the existing setpoi nt would require replacement of the existing switches.
The Technical Specifications allow a maximum containment pressure of 2.4 psig.
The bases for this limit is to provide an initial containment pressure which would limit the accident analyses maximum pressure to within the containment's design value.
Therefore the existing setpoint already contains a.4 psig margin, as well as the conservati sms built into the safety analyses.
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It is our position that the disruption to plant operation, the decoupling of containment pressure setpoint for CIS and SIAS (presently both at 5 psig),
and expense of replacing the existing instrumentation is not justified by any corresponding increase to the protection of the health and safety of the public.
Very truly yours, Robert E. Uhrig Vice President Advanced Systems and Technology REU/JEN/mbd cc:
ter. James P. O'Reilly, Region II Harold F. Reis, Esquire
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