ML20043G857

Proposed Tech Specs Re Deleting Automatic Closure Interlock on RHR Suction Valves

ML20043G857
Person / Time
Site:	South Texas
Issue date:	06/12/1990
From:	HOUSTON LIGHTING & POWER CO.
To:
Shared Package
ML20043G853	List: ML20043G852 ML20043G857
References
NUDOCS 9006210200
Download: ML20043G857 (10)

Text

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ATTACHMENT 2 PROPOSED TECHNICAL SPECIFICATION CHANGE 4.5.6.2.b and BASES 3/4.5.6 i

l 9006210200 900612 PDR P ADOCK 05000498 PDC j l

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. 7-EMERGiNCY CCRE C00llNG SYSTEMS

[ 3/4'.5.61 RE5100AL HEAT REMOVAL' (RHR) SYSTEM LIMIT *NG CONDITION FOR OPERATION .

- 3.5.6fThree independent Residual Heat Removal (RHR) loops shall: be OPERABLE

with'each loop comprised of:

a. One OPERABLE RHR pump,

b. One OPERABLE RHR heat exchanger, and

c. 40ne OPERABLE flowpath capable of taking suction from its associated RCS hot leg and discharging to its associated RCS cold leg.*

APPLICABillTY: MODES 1, 2 and 3. . ,

j ACT10th a, With one RHR loop inoperable, restore the required loop to OPERABLE -

status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />,

b. With two RHR loops inoperable, restore at least two RHR loops to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in at least HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />,

c. With three RHR loops inoperable, immediately initiate corrective

. action to restore at least one RHR loop to OPERABLE status as soon as possible.

$1)Ry[]1 LANCE RE0VIREMENTS

4. 5. 6.1: Each RHR loop shall be demonstrated OPERABLE pursuant to the require-mentsiof Specification 4.0.5. -

5 4.5.6.2 " At least once per 18 months by verifying automatic h;':t'... . inter-lock action of the RHR system from the Reactor Coolant System to ensure that:

3 With a simulated or actual Reactor Coolant System pressure 4

signal 'g'reater than or equal to 350 psig;-the interlocks -

prevent the valves f rom being opened, and .J

-4m---Wth-a-simuisteFor-actuai-Reecter Goalant Sys-tem-peettum-J gnal lets-thar. er v4dai-te 700 poig, T.he intw h k. ;11- -

--cause-the-vehes-to-automRkelly du==.

? " Valves MOV-0060 A, B, and C and MOV-0061 A, B and C may have power removed l

to support the- FHAR (Fire Hazard Analysis Report) assumptions.

SOUTH TEXAS - UNITS 1 & 2 3/4 5-11 Unit 1 - Amendmer No. 4

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EMERGENCY CORE COOLING SYSTEMS BASES

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3/4.5.6 RESIOUAL HEAT REMOVAL (RHR) SYSTEM

'[ The OPERABILITY of the RHR system ensures adequate heat removal capabili-ties for Long-lerm Core Cooling in the event of a small-break loss-of-coolant

p. accident (LOCA), an isolatable- LOCA, or a secondary break in IODES 1, 2, and 3. -

The limits on the OPERABILITY of the RHR system ensure that at least one RHR l t loop is _available for cooling including single active failure criteria, i

-The-surveil l ances-ensure-that-RHRW5temisolati nn-val ves-cl ose-upon-an

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ATTACHMENT 3 i MARK-UP OF THE FINAL SAFETY ANALYSIS' REPORT j t-s i -. )

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i I l TASLE 1.3-2 (Continued) s SIGIIFIC4lli DESIGl CNNNIES l

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! References i tten UFSAR Description of Channe i

l I euellfled sisA oy Processing section 7.5 Addition of safety-related diepter processing system which provides redimdent data i system (eges) . acapaisitten and display. System provides Class 1E control of the SG power-operated relief watwes, heed vent throttle vatwes, AFW f tcu regulating volves, and ECW throttle vatwo for the assential chitters. The s pten ateo performs SG reference ,

tog temperature campensation and RCS hot tog temperature overaging calculations.

Emersoncy acepense Facilities section 7.5 Provides signet processing and display for Emergency Reaperse Facilities and f addresses SPDS respairement of MUREG e6e6.

j Sota Acapsisition and sleptay Letdoom Step wetves section 7.6 Changes to letdeem isolation signets. ' 1he pressurizer Lou towel interlock closes f the valves and prevents the operator from responing them from the main control room m

' Pressurizer tswel Interlocks H intil the pressurizer unter towet is above the setpoint. The closure signets to each letdeem stop volve are delayed so that chemstream velves can etcae before the $

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. stop valves, to prevent flas!.ing in the regenerative heet encharger. g Reactor Cootent Purity Centrot sections 7.6, 9.3.4 Addition of espalpment to aset more stringent reactor makeg unter chemistry @

l- h parameters. Addition of safety grade isotation vetwes. ua l

' h Tell Action Plan Requirements Appendia 7A MMREG G737 andificctions including post accidmett sampling system, post-accident monitoring e9 grades,a9 grades to emergency response capabilities, etc.

lastrumentation and Centrot . Sections 7.6, 8.3 Empension of system for channets I and IV.

Paesar Snaply System (Class 1E) ( >

~ 7 Addition of toSics for automatic closure of vetres edien above setpoint pressures [ Y sesidiant' meet memoves. Sections 7.6, 5.6 Isotation vetve Lesic -

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!i- Centeiament sydrogen Section 7.6 Key tack seeltches for the sampling and ContefamerG isolation vetwos are deleted.

stenitoring System Sempting points and monitor ranges changed.

Intertecks for SCS Pressure section 7.6 Addition of safety-grade topic for cold overpressure mitigation, using safety-Centret sharing Loss Temperature grade transmitters, topic, and pressurizer PORVs.

W atten o

Section 7.6 Addition of safety-grade Logic to close the sprey achsittwo tank isolation vatwo en Spray Addittwo Tasdt Lons-Loss Levet lateric:k- when the tank fluid reaches the Ices-Lees levet setpoint.

o Acklition of logic generating C-17 interlock and its use to step turbine toeding.

,3 Control Interteck C-17 Section 7.7 O-

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s COLD SIRJTOGAI FAltuRE en0 DES AIS EFFECTS AIIALYSIS ._

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4 Plant feethod - Felture Effeet-Description Safety Operating Felture' Of Feiture- On System Safety '

Of C m t Ftmetion stode* Stade(s) Detection Ftmetion Cemet>itity Generet Resorte Residuet fleet Removet System RtIR Pump 1A Operate and 4-5 Felts to Pisup flow and Isons - Tuo rossident (see Figure 5.4-6)

(pumpo 18 and provide cootent operate discherpe RIIR pumpe ovelletde Lees of pamp eer result i 1C enetogous) flow for RIIR preneure in longer cootdeun time operation Indication and indicator tights et lets $

'S t.n p stotor-operated open to attou 4-5 Either volve Vetve position Isone - Redadent Rult E

- gate volves asut flow felts to indication, pump treine provide cooling to l Y se0W-0060A and open on flow indication c:

• • desond or and eters and die- M i

IIDW-0061A

" once open, charge pressure

( (volves fiDV-00608 and felts ctooed_ indication et fets 81C000613, (e.g., false 940W-0060C and auto-closure

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se0W-0061C signet) /

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(nornetty closed) l t

l Close to lootste 4-5 Falls to close vetve positlen teone - Redmelant voivos -

l the R41R system indicetten, pres in eerles provide l

from the RCS sure and temperature foototion Indicatione et IES ,

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1. Power Operation 4. Isot shutdoun  ;

( 2. Startip 5. Cold shutdoun

3. Isot Stancery 6. Refueling ,

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. 4 STPECS UFSAR 3l[

m 7.6.2 Residual Heat P,emoval Isolation Valves

• 1 7.6.2.1 Description. There are two motor operated gate valves in

- series in each' inlet line from the Reactor Coolant System (RCS) to the

Residual' Heat Removal System (RHRS), as shown on Figure 5.4 6. They are

- normally closed and are manually opened from the control room for residual heat removal ~(RHR) after RCS pressure and temperature are reduced to ,

approximately 400 psig and 350'F, respectively. As shown on Figure 5.4 6 and t on the control logic (Figure 7.6-2), the two valves in each RHR inlet line are l powered from different Class 1E power sources. Additionally, power is locked 3

at the motor control center (MCC) breaker for the valve closest to the RHR pump to mitigate the consequences of spurious opening of the valves during plant operation.

These valve 5 are controlled by three RCS wide range pressure transmitters, shown on Ptgure 5.1 1. The transmitters, PT 405, PT 406, and PT 407, are  !

i located outsid the Containment. Conformance of the design to Containment

-isolation requirements is discussed in Section 6.2.4. Two additional RCS wide range pressure transmitters, PT 403 and PT 404, are also shown on Figure 5.1 1. These transmitters are used for RCS cold overpressure mitigation (via the pressurizer power operated relief valves (PORVs)). These two. transmitters are located inside the Containment. Table 7.6 1 shows the manufacturer, model number, protection set assignment, and RCS loop monitored for each d_

transmitter.

The signal from each tr3nsmitter controlling the RHR inlet isolation velves providesitwo functions 1) a permissive that allows valve opening below a preset  !

pressure cand_an autom_atic closure on pressures above-a p.raset val g The open permissive ensures that the valve is not opened when the RCS pressure plus the RHR pump discharge pressure is-above the RHRS design pressure. The two valves in each RHR train receive pressure signals from different pressure transmitters, through the Engineered Safety Features (EST) actuation train o corresponding to the train of power supplied to the valve.

7.6.2.2 Analysis. The applicable requirements of IEEE 308-1974 are applied to the electrical power supply for the RHRS pump motors and to the 16C for the' motor operated RHR inlet isolation valves. Based on the scope 1 < definitions presented in IEEE 279 1971.and 338 1971, these criteria do not

.o apply to the RHR isolation valve interlocks; however, in order to. meet Nuclear

, . Regulatory Commission (NRC) requirements and because of the possible severity of the consequences of loss of function, the requirements of IEEE 279 1971 are applied with the following comments:

1. For.the purpose of applying IEEE 279 1971 to this circuit, the following definitions are used.

a. Protection System L

l .The two valves in series in each line and the components of their interlocking (((ndclosur circuits.

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'b. Protective Action w $

'Against Normal _RCS Pressures )

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Against normal RCS pressures, the protective action is the automatic initiation and maintenance of RHRS isolation from j the RCS when RCS pressures are above a preset pressure. l To Assure Operability of One RHRS Train j

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For assured plant cooldown, the protective action is the removal of the +utomaric- RHRS inletish when RCS pressure is l below a preset pressure. huhgjeeg L

2. 'IEEE 279 1971, Paragraph 4.10: The above mentioned pressure interlock signals and logic are tested en line to the maximum extent possible without adversely affecting safety. This test includes the analog i signal through to the actuation train signal which activates the slave relay.(the slave relay provides the final tput signal to the valve __ .

control' circuit). This test verifies he protective action (;THIT' sagainst i

normal RCS pressures)and assures operabi ity of one RHRS train.

~donet in the best incerest of- safety since opening the valve could potentially leave only one remaining valve to isolate the low pressure i RHRS from the RCS. >

r Since the two valves in each RHR train are powered by separate power trains and actura:ed by separate actuation trains, no- single failure can compromise the required RHR functions.~FIsolation against normal RCS pressures (above I

/' preset pressure) is assured by redundant valves, diversely actuated and powe d end by tha power lockout on one valve in each train. f uperability for i assured plant cooldown is' assured because a faTTuie in any one actuation or power train isolates only two trains, leaving the third train still operable.

Branch Technical Position (BTP) ICSB 3'is followed for this interlock system.  ;

-The interlock system meets the appropriate qualification standards, as discussed in Sections 3~.10 and 3.11, 7[6.3. Accumulator Hotor Operated Valves In considering that the requirements of IEEE 279-1971 apply to protective actions at both the channel level and system level, it is noted that for the

. accumulator isolation valves, the basis for control and proper functions is administrative control and passivity; the scope of IEEE.2791971 covering

_ protective action at the system level does not apply, although there is a j requirement for protective action at the channel. invel. The interlock control j

' features.of the accumulator isolation valves at the channel level function in a lconfirmatory manner._ and the requirements of IEEE 279 1971 are applied with ithe following comments:

l '. When the pressurizer pressure is above or below the P-11 setpoint '

(approximately 1,900 psi), there are redundant interlock signals generated that are derived by sensors processed through circuitry designed to IEEE 279-1971 requirements in the analog process control racks and distributed as binary input (voltage /no voltage) signals to the' Solid State Protection System (SSPS) cabinets. Here they become L logic signals that produce contact available outputs from the safeguards 7.6-3 Revision 0 I

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