ML18029A280

Proposed Tech Specs Re Removal of Requirement for Initiation of Reactor Scram on Condensor Low Vacuum

ML18029A280
Person / Time
Site:	Browns Ferry
Issue date:	11/19/1984
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML18029A279	List: ML18029A278 ML18029A280
References
NUDOCS 8411270269
Download: ML18029A280 (40)

Text

'Eg ENCLOSURE 1 PROPOSED TECHNICAL SPECIFICATION REVISIONS BROMNS FERRY NUCLEAR PLANT (TVA BFNP TS 204) f 84ii2702b9 PDR ADOCK 84iii9 05000259 P PDR ~

UNIT 1 PROPOSED SPECIFICATIONS

SAFETY LIMIT LIMITXNG SAFETY SYSTEM SETTING

1. 1 FUEL CLADDING INTEGRITY 2.1 FUEL CLADDING INTEGRITY B Power Transient To ensure that the Safety Limits l. scram and isola- I above 538 in.

established in Specification {PCIS groups

1. 1.A are not exceeded, 2,3,6) reactor low vessel

'ach required scram shall be water level zero initiated by its expected scram 2. Scram--turbine S 10 per-signal. The Safety Limit shall stop valve cent valve be assumed to be exceeded when closure closure scram is accomplished by means other than the expected scram 3, Scram--turbine 550 psig signal. control valve fast closure or turbine trip,

4. (Deleted)

5. 'Scram main 5 10 per-steam line cent, valve isolation "losuro 6, Main steam isola- ~825 psi" tion valve closure

<<-nuclear system low pressure C. Reactor Vessel Water Level C. Water Level Tri Settin s Whenever there is irradiated

'fuel in the reactor vessel,

. Core spray and I 378 in.

LPCI actuation-- above

~

the water level shall. not be reactor loM water vessel less than'7.7 in. above. the level zero top of the normal active fuel HPCI and HCZC 470 actuation zone.

reac- above tor low water .

vessel level zero Main steam isola- h 378 in.

tion valve clos ur e

'bove r eactor Vessel water level 'ow zero

P

2. 1 BASES

~ I

~ t t ~

1~ (DELETED)

C. 6 H. Hain Stags Line Is~ wtion on LoBB Prcssure and Hain Steam Line Isolation Scracs The lov pressure isolation of the main steam lines at 825 psig vss provided to protect against rapid reactor depreasurization and the

'esulting rapid cooldovn of the vessel. Advantage is taken of the scram feature that occurs vhen the main steam line isolation valves are closed, to provide for reactor ahutdovn ao that high povsr opera-tion at lov reactor preoeur does not occur, thus providing protection for the fuel cladding integrity safety limit. Operation of the reac-tor at pressures lover than g2> psig requires that the reactor cade

~ Mitch be in the STARTUP position, vheze protectfon of 'the. fuel cladding safety limit is provided by the IRM and APRM high neutron flu'x 'ntegrity acrams. Thus, the cotsbinstion of main steam line lov pressure isolation and isolation valve closure scram assures the availability of neutron flux scram protection over the entire range 'of applicab'lity of the fuel cladding integrity safety liBBit. In addition, the isolation valve closure scram anticipates the pressure and flux transients that occur during normal or inadvertent isolation valve closure. With ths scrams

~ et at lO percent of valve closure, neutron flux does not increase,

t TABLE 3 1nA REACTOR PROTECTION SYSTEM (SCRAM) INSTRUMENTATION REQUIRENEtIT Min. No.

of Operable Ins't o Modes in Qhich Function Channels Must Be 0 erable Per Trip o 8 hut- Startup/Hot

~snt n 1$ ( 3) ".Itto Innttton Tri Level =ettin =onn ~nntntl I I".nntt I n n~ntio Main Steaa Line Isola-tion Valve Closure 5 10% Valve Closure X(3) (6) X{3) (6) X(6) 1.A or 1.C Turbine Cont. Valve Past Closure or k 550 peis X(4) 1 A or 1 D Turbine Trip Turbine Stop Valve Closure S 10S Valve Closure X(4) 1 A or 1 D 2 . Turbine First Stage Pressure Permissive not 8154 psis X{18) X (18) X (18) (19)

I

2. ~

Main Steam Line High 3X Normal Full Paver X(9) X(9) X(9) 1.A or 1.c Radiation (14) Background(20)

0 TABLE 4.I.A, REACTOR PROTECTIOH STSTEH (SCRAH) IH~iUHBfTATIO!lPUHCTIONAL TESTS HDiOSH FUHCTIOHAL TEST FkPPEHCIES POR SAP ETT IHSTR. AHD COHTRDL CIRCUITS

%au Functional Teat Hfnfnun fre ueacy (3)

Hode Svftch ia Shutdovn Place Hode SMitch in Shutdovn Each Refueliog Outage Haaual Scraa A Trfp Channel and Alar>a Every 3 Hontha IRH High flux Trip Channel and Alake (4) Once Per Meek Durfag lefuelin and Before Each Startup Inoperative- C . Trip Channel and Aiara (4) Oace Per Meek During kefuelin and Before Each Startup APRH High flux (1ST acraa) Trip Output Relays (4) Before Each Startup and Meeki When Required to be Operable High Flux (Flow Biased) Trip Output Relays (4) Once/ljeelc Hfgh tluz (Fixed Trip) Trip Output Relays (4J Inoperat fve Trip Output kelaya (4) Once/Meek Douna ca le Trip Output Relaya (4) Once/Meek PIov Eiaa (6) (6)

Rfgh Reactor Preaaure Trip Channel and Alarm Once/Honth (1)

High Dryvoll Preeaure Trip Channel and Alarm Once/Honth (1)

Reactor Lou Meter Level Trfp Channel aad Alara Dace/Hoath fl) .

High Water Level in Scram Discharge

.Tank

. Float Skitches Trip Channel and Alarm Once/Month (LS-85-45C-F)

High Water Level in Scram Discharge Tank Tr'ip Channel and Alarm (7) Once/Month

'lectronic Level Switches (LS-85-45A; B, G, H)

Hain Steam Line. High Radiation B Trip Channel and Alarm'4') Once/3 months (8)

TABLE, 4 1 ~ B REACTOR" PROTECTION SISTEM (SCRAM) XNSTRVMENT CALIBRATXON MXNXMVM CALIBRATIOM FRE()azrs:IES FOR REAcroR PRoTECTzoN XNSTRVMENT CHANNELS Instrument Channel Qroup (1) calibration Minimum Frequency (2)

IRM High Flux c Compari,son to APRM on Control Note (4) led startupa (6)

APRM High Flux Once every 7 days Output Signal B Heat Balance Flow Bias Signal B Calibrate Flo<< Bias Signal (7) Once/operating cycle LPRM Signal B TZp System Traverse (8) ~

Every 1000 Effective~

Full Power Hours High Reactor Pressure Standard Pressure Source Every 3 Months High Drywell Pressure Standard Pressure Source Every 3 Months Reactor Low Mater Level Pressure Standard Every 3 Months High Water Lovel in Scram Discharge Volume Float S~itches Calibrated Water Column (5)

(LS-85-45 C-F ) Note (5)

High Water Level in Scram Discharge Volume Electronic Level britches i br a to d (LS-85-45-A, B, G, H) B Ca 1 Wa t er Co 1 umn Onco/Operating Cycle (9)

Isolation Valve Closure Note (5) Note (5)

. Hain Steam Line

'ain Steam Line High Badiation Standard Current Source (3) Every 3 Honths I 0 Turbine First Stage Pressure Permissive Standard Prcssure Source (PT-1-81A and B, Pl'-1-91A and B) B Once/Operating Cycle (9)

Turbine Cont. Valve Fast Closure or. Standard Pressure Source Once/Opera tin8 Cyc 1 e Turbine Trip Turbine Stop Valve Closure Note (5) Note (5)

3.i slsEE It modes. In the pover range the APLi system pzovidos requ 4 tod protection.

Ref. Section 7.5.7 PSAR. Thus, the IRH System ie not required in the Run mode. The APRM's ond tho IRN's provida adequate covet>>go in the startup and intermediate range.

The high reactor .pressure, high dryvell pressure, reactor lov vater level and scram discharge volume high level scrome are required for Startup and Run aedes of plant operation. They are, therefore, required to be opera-tional for these modes of'eactor operation.

The requirement to have tho octan functions as indicated in Table 3.1..1

'perable io the Refuel etode is to oeauze that shifting to the Refuel mode during reactor pnvcr operation does not diminish the need for the reactor protection syste~.

Because of the APL'ovnscole limit of > 3Z vhen in the Run mode and high level limit of < 15I vhen in the Startup Hode, the transition betvoen tho Startup and Run Nodes must be made vith the APRH instrumentation indicating betveen 3I and 15I of rated paver or o control rod octan vill occuz. In addition, the IRf system must be indicating belov tho High Plux setting (120/125 of ocale) or a scram vill occur vhen in tho Startup Mod>>. Pot normal operating conditions, those limits provide assurance of ovet'lap botreen the IRH system and APLf system eo that thoro aze no "gape" in the paver lovel indicetione (i.e., the pover level ia continuously nanitorad from beginning of etartup to full povor and fton full pover to ehutdovn).

4hen povet ie being reduced, if a tran>>fez to the Startup mode ia tuLCo end th>> IL'l'e have not been fully inserted (a maloperationol but not Mpoeeiblo condition) a control rod block ~odiatcly occurs so that reactivity meez-tion by control rod vlthdraval cannot occur.

44

UNIT 2 PROPOSED SPECIFICATIONS A

~

0

~

SAFETY LIMIT t ~~ <<l SAFETY SYSTEM SETTING ..5'IMITING P~-

l. 1 FUEL CLADDING INTEGRITY 2. 1 FUEL CLADDING INTEGRITY

'ower Transient B. Power Transient Tri Settin s To ensure that the Safety Limits l., Scram and isola- h 538 in.

'stablished in Specification tion (PCIS groups above

1. 1.A are not exceeded, 2,3,6) reactor low 'essel

• 'each required scram shall be ,

water level . zero initiated by its expected scram signal. The Safety Limit shall

2. Scram turbine 5 10 per-be assumed to be exceeded. when stop valve cent valve closure closure scram is accomplished by means other than the expected scram 3, Scram--turbine ., = 550 psig signal. control valve fast clo"ura or turbine trip 4 (Deleted) main 5, Scram steam isolation line

.

'. 5

.

1,0 per-cent valve "losuro 6, 'Main steam. isola-

'I

~825 'sig 0ion valve closure nuclear system low pressure C. Reactor Vessel 4'ater Level C. Water Level Tri Settin s whenever there is irradiated . Core spray and h 378 in.

fuel in the reactor vessel, 'pCI actuation

'water above

~ the water. level shall not be reactor lofti vesaeT less than 17.7 'in. above the level xero top of the normal active fuel HPCI and RCIC 470 zone.

actuation reac- 'bove tor low water,. vessel level zero 3~ Main steam isola- ~ 378 in'.

. tion valve , above closure--reactor vessel low water level . zero R

(

~

~

. (

( (A ((t ~

X((44( ~ ~ ( ~,

4

~, ( (l

~ 1 RLSES

'

~ ~

(

' l ..a

( ' ( ~ ~

~>>

(DELETED)

'C. 4 H. lhin Staaa Line Is~ ation on Lov Pressure and Rain Stepan Line Isolation Scran

'fhe lov pressure isolation of the mein stean lines at 8Z5 psig veN

- provided to protect esainet rapid reactor depressuri,zation and the resulting rapid cooldovn of the vessel. Advantage is taken of. the icr(aa feature that occurs vhen the aain stean )ine iso)ation valves are closed, <<o provide for reactor ahutdova so that high pover.opera-ciern at lov reactor proosur does not occur, thus providing protection for the tuel cladding integrity safety limit. Operation of the reac-

<<or at pressures lover'han 8Z> poig requires that the reactor code avitch ba in the.STAR'LVP position, vhere protection of the fuel cladding integrity safety )Snit ia provided by'the IRM and APRH high neutron flux

~

oczans. Thus, the conbination of nein utean line lov pressure.isolation and isolation valve closure acracl assures the availability of neutron Flux acraa protection over the entire range of applicability of the fuel cladding integrity safety limit. In addition, the isolation valve closure ecraa anticipatea the pressure and flux transients that occur durini noaaal or inadvertent isolation valve closure. Mith the scree oet ot 1Q percent of valve closure, neutron i'lux does not increase.

TABIH '3.1 ~ A REACTOR PROTECTION SYS EM (SCRAM) INSTRUMi8TATION REQUIREMENT Kin. No.

of Operable Inst. Modes in Nhich Function Channels Must Be 0 erable Per Trip Shut- Startup/Hot Tri Level Settin dovn ~Re.'uel 7 Stan~db RGll ~IICt1Oll 1 Main Steam Line Isola-tion Valve Closure 5 10% Valve Closure X (3) (6) X (3) (6) X (6) 1.A or 1.C Turbine Cont Valve ~ ~

Past Closure Or k 550 pais X(4) 1.A or 1.D Turbiae Trip Turbine Stop Valve Closure 6 10S Valve Closure X(4) 1.A or 1.D 2 - Turbine First Stage Pressure Permissive nor F154 psi8 X (18) X(18) X(18) (19) 2 Main Steajs Line High 3X Normal Full Power X(9) X(9) X(9) 1.A or 1.C Radiation (14) .Background (20)

TABLE 4m 1.A REACTOR FROTRCTlOM STSTF8 (SCRAH) DlSTRUHWTATlOR FUNCTlONAL TESTS HfHOSH HSCTfONAL TEST FREQUENCIES FOR SAFETT lNSTR. AND CONTROL CIRCU?TS QEn~g Functional Teat Hiataun Fr ueacy ($ )

Mode'Svitch ta Shutdova A Place Mode Suitch tn Shutdoua Each Retuettag Outage Haaual Scran A Trtp Channel aod Alarm Every 3 Hoatha TRH High flux Trip Channel and Afana (4) Once Pcr Meat Durfog Refueltn aad gefote Each Startup Inoperatfra Trip Channel and Alara (4) Once Per Meek Duriag Rcfueltn aad gcfore Each Startup APRH High Flux (1$ Z acraa) Trip Output Relays (4) before Each Startup aad Mcekl Mhca Required to be Operable High Flux (Flow Biased) B Trip Output Relays (4) Once/Week High Flux (Fixed Trip) 5 Trip Output Relaya (4) Dace/Meek lnoperatfre Trtp Output Relaya (4) Once/Mech Dovaacale Trip Output Relaya (4) Oace/Meek Flou gtaa

~

'

Cy

~

fffgh Reactor Preaeure Trip Channel and Alara Dace/Honth (1)

Ifgh Dryvell Preaaure Trfp Channel and 'lara Dace/Hoath (1)

Reactor Lov Mater Level Trip Chaaael'aad Alaa ~

• Once/Honth (1).

High Mater Level f a Scree Dtacharge Tank Float Switches 3 A Trip Channel and Alarm Once/month Differential Pressure Switches B . -

Trip Channel and Alarm " Once/month (7)

Main Steam Line High Radiation Trip Channel and Alarm On'e/3 months (8)

TABLE 4 1~B REACTOR PROTECrloH sysTEH (SciAH) IHSTROMEHT CALIBRATIOH HIHIHUH CALIBRATIOH PREQOE)a IES FOR REACXOR PROTECTIOH IHSTROKEssr CHANNELS Instrument Channel Croup (1) Calibration Minimum Frequency (2)

IRH High Flux Comparison to APRH on Control- Hots (4) led scarcupN (6)

APRH High Flux Output Signal B Heat Balance Once every 7 days Flow Bias Signal B Calibrate Flow Bias Signal (7) Once/operating cycle LPRH Signal TIP System Traverse (8) Every 1000 EI(ective Full Power Hours High Reactor Pressure Standard Pressure 'Source Every 3 Months Bigh Orywell Pressure Standard Pressure Source Every 3 Months ReaCtOr LOw Water LeVel Pressure Standard Every 3 Months High Water Level in Scrafa Oischarge Volumes Float Switches A Note (5) Note (5)

Differential Pressure Switches B Calibrated Mater Column Once/Operating Cycle

. Main Steam Line Isolation Valve Closure A Note (5) Note (5)

Main Steam= Line High Radiation B Standard Current Source (3) Everv 3 Months Turbine First Stage Pressure Permissive A Standard Pressure Source Every 6 Months ur n; Turbine Stop Valve Closure Turbine Cont; Valve Fast Closure or Turbine Trip A

No'te (5) a<<a<<p'ressure Sour Note (5)

Once/operating cycle

modes. In the paver raRge the APRH system provides requ'rod'protection.

Ref. Section 7.5.7 FSAR. Thus, the IRH System io noc required in the hand mode.

Run The APRH' aad tho ILN'a provide adequate coverage,in the etartup and incermediate range. 4

. The high reactor -pressure, high dryuell pressure, reactor lov voter level scram discharge volume high level seroms are required for Stortup and Run sades of plant operation. They are, therefore, required to be .opera-tional for th es>> modes of'eactor o P eration.

The requirement to have the scram functions as indicated in Table 3.1.1 operable io the Refuel mode is to assure that shifting to the Refuel sade during reactor pover operatioa does not diminish the need for. the react'or protection systems I

Because of the APRH dovnseolo, i limit of 3X vhea in the Run mode and high limit of c15I uhen in the Startup Hode, che transi'cion betuoea the 'evel Startup and Run Hodes must be made vith the APRH instrumentatioa indicatiag betveen 3X and 15X of rated pover or o eon'trol rod scram vill occur. In

~ ddition, the IRH system must be indicating belov the High Plux setting (120/125 of scale) or a scram vill occur vhen 'ia the Stsrtup Mode. For normal operating conditions, those limits provide assurance of over'lap betveon the IRH system and APRf system so that there are ao "gapa" ia the pouer level indieationo (i.e., the pouer level is continuously cmnitored

!rom beginning of startup to full paver aad from Cull pover to pover is being reduced, if shutdovn),hen o transfer to ths Startup 'mode ia made sad IRN'e have not been tully inserted (a maloperotioaol but'ot impossible 'he condition) o control rod block ~odiatcly occurs so that rsactiv'ty macr<<

tion by control rod vithdraval esaaot occur.

0 UNIT 3 PROPOSED SPECIFICATIONS

~ SAFETY LIMXT 'LIMITING SAFETY 0 SYSTEM SETTING 1.1 FUEL CLADDING XNTEGRXTY 2 1 FUEL CLADDING INTEGRITY Power Transiene B. Power Transient Tri Settin s To ensure that the Safety Limit s Scram and isola- h 538 in established in Specification tion (PCXS groups above

1. 1.A are noe exceeded, 2,3,6) reactor low vessel

'ach required scram shall be water level zero initiated signal.

by its expected scram The Safety Limit shall

2. Scram turbine 5. 10 per-stop valve cent valve be assumed to be exceeded when closure closure

'scram is accomplished by means other than the expected scram Scram--turbine 550 psig signal. control valve ~

fast clo"ura or eurbino trip

4. (Deleted)

5. 'cram--main 5 1Q per-steam line cent valve isolation .. closur~

Main steam isola- ~ 825 psi",

tion valve closure nuclear system low pressure l

I C. Reactor Vessel Mater Level C. Mater Level Tri Settings Mhenever there is irradiated .

fuel in the reactor vessel, Core spray and LPCI actuation I 378abovein.

~ the waeer level shall noe be 'reactor 1oii water vesaeT less than'7.7 in. above the level zero.

top of the normal aceive fuel 2, HPCI and RCIC 470 actuation zone.

reac- above tor low water vessel level zero Main steam tion valve isola- I 378 in.

above closure--reactor vessel low water level zero

" 13

~ ~

.~ iJ" oil pressure at. the main turbine control valve actuator disc dump valves~a, This loss of pressure is sensed'by pressure switches whose contacts form..;

the one-out-of-two-twice .logic input to the reactor protection system.

This trip setting, .a -nominally 50X greater closure time and a different valve'characteristic from that:.ef the turbine stop valve,,combine to produce transients very similar to that for .the stop valve.

Relevant transient analyses are'=discussed in References 1 and 2. %This scram is bypassed when turbine steam flow is below 30/ of rated, as measured

,bv the turbine first staae oressure.

F (DELETED)

G. 6 H. Main Steam Line Isolation on Low Pressure and Main Steam Line Isolation Scram The low pressure isolation of the main steam lines at 850 psiq was provided to protect against rapid reactor

'epressurization and the resulting rapid cooldown of the vessel. Advantaqe is taken of the scram feature that. occurs when the main steam line isolation valves are closed, to provide for reactor shutdown so that high power operation at

.

low reactor pressure does not occur, thus providing protection for the fuel cladding integrity safety limit.

Operation of the reactor at pressures lower than 850 psig requires that the reactor mode switch be in the STARTUP

. 23

TABLE .3.1.A (cont'd)

REACTOR PROTECTIOH STSTEH (SCRA'1) IHSTRIlHEHTATIOH REQUIREIKNT dfnictun Hunbcr sf Operable Hodcs in Mhich Function instru=ent 1'.ust be 0 erable

hannels Pcr 23 Trf Punctlon High Mater Level in < 50 Trf Level Settin gallons itlliiml X

~lt t X(2) 1 ( ~Sia X

'lu StartuplHot dh X

'Aetio 1.i 1

East Scran Discharge Tank (LS-85-h5E-H)

}fain Stean Line c 10 percent valve closure X(6) 1.A or 1.C Isolation Valve Closuro 2 Turbino Control Valve Past Closure or i 550 psig X(h) 1 A or 1.D Turbine Trip Turbine Stop Valve c 10X Valve Closure X(4) 1.A or 1.0.

Closure Turbine First Stage not i 154 psig X(18) X(18) X(18) (19)

Pres'sure Pcrnfssfvc Main Stean Line High 3X Homal Full Pouer X(9) X(9) X(9) I.h or 1.C Radfatiun (14) Bac'kground (20)

P TABLE 4 ~ 1 ~ A REACTOR PROTECTIOII SYSTEH (SCRAM) I HSTRUHEHTATIOH FUHCTIOHhL TESTS HIIILLIUH FUIICTIOIIAL TEST FREQUQICIES FOR SAFETY IIISTR AND COIITROL CIRCUITS

~Gro 2 Functional Test Hinigug Frequency (J)

Hode Switch in Shutdown Place Hode suit,ch in Shutdown Each Refueling Outage Hanual Scrag Trip Channel and Alarg Every 3 Honths IRH lligh Flux Trip Channel and Alarla {4) Once Per Meek D ring Refueling and Before Each Startup Inoperative Trip Channel and Alarg {4) once Per Meek Dur(ng Refueling and Before Each Startup APRH Iligh Flux (15%.scrag) Trip Output Relays (4) Defore Each Startup and Meekly Mhen Required to he Operable

<I "~

{l)(,h Flux (Flou I)iased) Trip Output Reiays (4) OIIce/Meek (Fixed Trip) Trip IxItput Relays (p) Oncatuaap h

w Inollerative Trip Output Relays (4) Once/Meek Downscale Trip Output Relays (4) Once/Heck Flow Blas {6I (6)

Illgh Reactor Pressure Trip Channel and Aiarg Once/Honth (I)

High Dryuell Pressure Trip Channel and blare Onco/Honth ( I)

Reactor Lou Mater Level Trip Channel and Alarg Once/Honth (1) lllgh Mater Level in Scrag Discharge Tank Float.S'uitchcs (I.S-II5-45C-I') h Trip Channel and Alarg- Onci "lonlh fluctronlc Lovel Switches .. B I FIp Chnnnul In(I AI'Irm 0) Cnce/:AIuth (LS-85-45A, II, G, II)

TABLE 4 1 B REACTOR PROTECTION SYSTEH (SCRAH) INSTRUHENT CALIBRATION HINIHUH CALIBRATION FREQUENCIES FOR REACTOR PROTECTION INSTRUHENT CHANNELS I

Instrument Channel Group (1) Calibration Hinimum Frequency (2)

C IRH High Flux Compari.son to APRH on Control- 'tiote (4)

).ed stsrtups c (6)

APRH High Flux Output signal B Heat Balance Once every 7 days Flow Bias Signal B Calibrate Flow Bias Signal (7) Once/opera);ing cycle LPRH Signal B TIP System Traverse (8) Every 1000 Effective Full Power Hours High Reactor Pressure Standard Pressure Source Every 3 Honths High Drywell Pressure Reactor Low Mater Level Standard Pressure Source Pressure Standard

. Every 3 Honths Every 3 Honths e

High Mater Level ln Scraa Discharge Vo luce Float Switches (LS-85-45C-F) Calibrated Mater Coluon (5) )(ot e (5)

Electronic Level Sul'tches (LS-()5-4 l. 8, 0, K) Calibrated Mater Colucn Once/Oporsllng Cycle (9)

Hain Steam Line Isolation Valve Closure Note (5)

Note (5)

Hai n Steam Line High Radi ation standard Current Source (3) Every Turbine First Stage Pressure Permissive 3 Honths

'(urh(ne Cont. Vilve Fast Closure or Standard Pressure Source Every 6 Honths Turh(ne Trip Standard I'ressure Source Once(opal'at)ng cycle Turbine Stop Valve Closure- '

Note (5)

Note (5)

r which a scram would be function adequitely.

required hut not be able to perform its A source range monitor- (SRN) sysrlbea is also provided to supply additional neutron level information during startup but has rio scram functions Ref Section 7 5.0 TSAR Thus~ the IRM is required in the Refuel and Startup modes In. the pover range the APRM system pmvides xequired protection. Ref. Section 7 5 ~ 7

~

FsAR Thus~ the IRN System is not required in the Run mode.. The APRN~s and the IRM~s provide adequate coverage in the startup and intermediate range~

The high reactor pressure, high drywell pressure, reactor lmt water level and scram discharge volume high level scrams are required for Startup and Run modes of plant operation. They are, therefore, required to be operational for these modes of reactor operation.

The requirement to have the scram functions as indicated in Table 3.1.1 operable in the Refuel mode is to assure that shifting to .,

the Refuel mode during xeector poser operation does not diminish the need for the reactor protection systea.

Because of the APRM downscale limit of h 35 when in the Run mode and high level limit of 5 15% when in the Startup Mode, the transition between the Startup and Run Modes must be made with the APRM instnmentation indicating between 3% and 15% o'f rated power or a control rod scram will o'er In addition, the IRN, system must be indicating below the High Plex setting (120/125 of scale) or a scram norial opexating vill occur when in the Startup Node conditions, these limits provide assurance of For

overlap between the IRN eystoaa and APRN system so that there are no "gape" in the power leve1 indications (i e, the power level is continuously monitored from beginning of startup to full pover and from full pover to shutdown). Shen power is being reduced, if a transfer to the Startup mode is made and the IRM~ s have not been fu11y inserted (a maloperational but not impossible condition) a control rod block immediately occurs so that reactivity insertion by control rod withdrawal cannot occur.

43

ENCLOSUE 2 DESCRIPTION AND JUSTIFICATION (TVA BFNP TS 204)

Descri tion of Pro osed Chan es Units 1 and 2 - pages 11, 24, 34, 37, 40, and 44 Unit 3 - pages 13, 23, 33, 36, 39, and 43 The proposed revisions delete the requirement for initiation of a reactor scram on condenser low vacuum.

Reason These revisions are being proposed to preclude plant der ating,during periods of high condenser back pressure. These conditions exist primarily during conditions of high river water temperatures. These '

conditions have previously caused unit deratings. These proposed revisions, therefore, will allow an increased power output during conditions of higher than normal condenser back pressure.

Additionally, these proposed revisions will reduce surveillance testing requirements and decrease the probability of an inadvertent scram.

Justification and Safet Anal sis

'The basis for the turbine condenser low vacuum scram is to provide"

'an anticipatory scram to reduce the pressure increase of the reactor vessel caused ~onl by a turbine trip on low condenser vacuum. At greater than 154 psig turbine first stage pressure, the turbine trip would also cause a scram. In the accident and transient analyses, no credit is taken for this anticipatory signal; "therefore,, there will be no decrease in safety margins caused by deletion of this scram. Additionaly, the BWR Standard Technical Specifications

,contain no requirement for this scram.

ENCLOSURE 3 BROWNS FERRY NUCLEAR PLANT PROPOSED NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION (TVA BFNP TS 204)

The proposed change would delete the technical specification r equir ement in tables 3.1.A, 4. 1.A, and 4. 1.B for an automatic reactor pressure system initiation (scram) on turbine condenser low vacuum.

Basis for Proposed No Significant Hazards Determination NRC has provided guidance concerning the application of standards by providing examples of actions that are not 11kely to involve a significant hazards considerations (48FR14870). One example of actions not likely to involve a significant hazards consideration is a change which either may result in some increase in the probability or consequences of a pieviously analyzed accident or may reduce in some way a safety margin, but where the results of the change are clearly within all acceptable criteria wi.th respect to the system or component specified in the Standard Review Plan.

The proposed amendment does not involve a signif1cant increase in the probability or consequences of an accident or create the possibility of a new or different accident. The basis for the turbine condenser low vacuum scram is to provide an anticipatory scram to reduce peak pressure in the reactor vessel caused only by a turbine trip on low condenser vacuum.

Without the anticipatory scram at 23 inches of mercury vacuum on decreasing condenser vacuum, the main turbine would receive a trip at 21."8 inches of mercury vacuum. This trip signal would cause the turbine stop valves and control valves to close initiating a scram in less than one second. While the reactor was scramm1ng, there would also be an increase in reactor .

vessel pressure because of isolat1on of the main condenser, from the reactor. This pressure rise would normally be limi.ted by automatic open1ng of the turbine bypass valves. For the purposes of conservatively analyzing ~

tur bine trip transients, no credit was taken for either the condenser low vacuum scram or operation of the turbine bypass valves. Thus, deletion or nonoperation of the condenser low vacuum switches is conservatively bounded by the existing analyses and no decrease in safety margin is created. In addition, the Standard Technical Specificat1ons do not require this

'nticipatory scram.

Therefore, since the proposed amendment is encompassed by an example for which no sign1ficant hazards are likely to ex1st, TVA proposes to determine

'that the proposed amendment does not involve a signifi.cant hazards consideration.