ML20062G035
| ML20062G035 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 12/14/1978 |
| From: | Gilleland J TENNESSEE VALLEY AUTHORITY |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7812260163 | |
| Download: ML20062G035 (4) | |
Text
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TENNESSEE VALLEY AUTHORITY CH ATTANCCGA. TENNESSEE 37401 500C Chestnut Street Tower II DEC '4 1978 Director of Nuclear Reactor Regulation Attention:
Mr. Thomas A. Ippolito, Chief Branch No. 3 Division of Operating Reactors U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Ippolito:
In the Matter of the
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Docket No. 50-259 Tennessee Valley Authority
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i This is in further response to your letter of November 22, 1978, to N. B. Hughes concerning a request for additional information to complete your review of the reload analysis for cycle three operation of Browns Ferry Nuclear Plant unit 1.
The enclosed information supplements my letter to you of December 5,1978, and should fully address your Concerns.
Very truly yours, l
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'- J. E. Gilleland Assistant Manager of Power g
Enclosure 0
$y 781226o M3 f
An EcuM Occortundy Emcloyer
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i FURTHER RESPONSES TO.
I NRC QUESTIONS OF NOVEMBER 22, 1978, CONCERNING UNIT 1 RELOAD l
Question 9:
Document in appropriate detail that the end-of-cycle RPT systems will be part of the reactor protection system, will fdly conform to IEEE 279-1971, and will.be appropriately qualified as Class lE equipment.
Response
The EOC RPT system' logic is a part of the reactor protection-system (RPS) logic as indicated in the attached block diagram..The power for~the RPT logic comes f rom the same power supply sources used for the RPS. The RPT system is
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classified as Seismic Category 1 Class lE.
The system shall remain functional r
in the event of a design basis earthquake and shall provide a safety L
function to mitigate the consequences of the turbine / generator trip or load rejection event. The EOC RPT system (as is the RPS) is a fail safe system.
The design of the EOC RPT conforms to IEEE 279-1971.
Question 10:
In order that compliance with the single failure criterion can be verified, provide the control logic diagrams, P&ID's, and schematic diagrams for the RPT systems (including sensors, operating bypasses, and maintenance bypass features).
Response
4 The EOC RPT system has been designed in accordance with IEEE 379. The
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design shall be based on two separate trip divisions; each has i
separate trip channels, sensors, and associated equipment for each measured variable. The design meets the single failure criterion such that any single trip channel (sensor and associated equipment) or system component failure will not prevent the system from performing its intended ~ function.
The RPT system logic (as designed) will not cause the inadvertent trip of more than one pump given a single component failure in the system. Each trip division is clearly identified to reduce the.posaltility of inadvertent' j
trip of the recirculation pump during routine maintenance and test cperations.~
Redundant sensor circuits in each division (sensors, wiring, transmitters, i
f amplifiers, etc.) are electrically, mechanically, and physically independent so that they are unlikely to be disabled by a common cause.
Diagtans pertaining to the items discussed have been provided to you.
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. CLARIFICATION OF DECEMBER 5,1978, RESPONSE TO QUESTION 13:
Manual' initiation of the ECC RPT switchgear can be accomplished from the auxiliary instrument room or the remote breaker switchgear. However, the recirculation pumps can be manually tripped in the control room at any time by the operator using normal controls. The intent of IEEE 279 Section 4.17 is that the protection system includes means for manual initiation of each protective action at the same level. The EOC RPT is designed only to operate with turbine trip / load rejection above 30% power.
The EOC RPT is not the only system that can be used to trip the recirculation -
pumps.
C1.ARIFICATIUN OF DECEMBER'5,19787R55PWSE TO 'QUESTIONT4c:
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a The requirement of placing both RPT systems in test status during the duration-of the monthly surveillance tests has been previously identified as undesirable by TVA. Proposed modifications to the existing RPT design have been initiated within TVA's design organization for internal review and approval. The modification will be implemented as soon as feasible.
Question 14d:
Provide for procedures or propose a technical specification which provides for periodic functional testing of the RPT breakers.
Response
j The breakers will be functionally tested every operating cycle.
1 CLARIFICATION OF DECDfEER 5,1978, RESPONSE TO QUESTION 16:
The response time of the RPT logic will be checked in a manner consistent
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with measuring response times of the existing RPS logic.
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i PEPJilSSIVE WHEN PERMISSIVE WHEN PER4ISSIVE WHEN PERMISSIVE WHEN TURB STOP VALVE TURB CONTR VALVE TURI 3 STOP VALVE TURB CONRT VALVE CLOSED >10%
FAST CLOSE SIG CLOSED > 10%
FAST CLOSE SIG PRESEllT PRESENT PoS RPS*
PS RPS*
PoS RPS*
PS RPS*
1 PEPJilSSIVE WHEll PEPHISSIVE WHEN PERNISSIVE WHEN PERMISSIVE WHEN TURB STOP VALVE 11)RB CONTR VALVE TURB STOP VALVE TURB C0fiTR VALVE i
CLOSED > 10%
FAST CLOSE SIG CLOSED > 10%
FAST CLOSE SIG
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PRESEliT PRESENT PoS RPS*
PS RPS*
PoS RPS*
PS RPS*
I PERMISSIVE WHEN PERJ4ISSIVE WHEll j
FIRST STAGE FIRST STAGE TURB PRESSURE >
TURB PRESSURE >
l SETP0litT SETPOINT i
PS lRPS*
PS RPS*
PEPHISSIVE WHEN PEPHISSIVE WHEli FIRST STAGE FIRST STAGE 1
TURB PRESSURE 7 TURS PRESSURE >
l SETP0 lilt SETPOINT f
PS l RPS*
PS RPS*
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I PEmilSSIVE WHEN PERMISSIVE WHEN I
BYPASS SW Ill BYPASS SW IN "l10PJ t"
" NORM" I
l Ris CR RMS CR l
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l lRPT l RPT Y 3A 4A yDIV.1 TRIP y 3B 48 yDIV. 2 TR ENERGIZE BREAKER 3A & 4A TRIP COIL A ENERGIZE BREAKER 2B & 48 TRIP COIL A RECIRC PUMP A & B.
RECIRC PUMP A & B.
RECIRC PUMP TRIP (RPT)/RPS FUNCTION BLOCK OIAGRAM i
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