ML20024F112

Proposed Tech Spec Changes Revising Sections 2.3.1.6,2.3.7, 3.3 & Tables 3.1.1 & 4.1.1 to Allow Addition of Tenth Range to Neutron Monitoring Sys Intermediate Range Monitors

ML20024F112
Person / Time
Site:	Oyster Creek
Issue date:	09/02/1983
From:	GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20024F110	List: ML20024F109 ML20024F111 ML20024F112
References
NUDOCS 8309080240
Download: ML20024F112 (9)

Text

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2.3 LTli! TING SAFF.TY SYSTDf _ST.TTINGS_ .

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e ,2 11_cabil h_EE: Applies to trip settings on automatic protective devicca related to variabics on which safety limits have been placed.

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Obicetive: To provide automatic corrective action to prevent the safety limits. from being creceded. ,

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Speci fic.1 tion: Liniting safety system settings shall be as follows: .

. FUllCTION LDf1 TING SAFETY SYSTD! SETTINGS -

1) Ncutron Flux, Scram APRM

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For recirculation flov, W<61 x 10 6 lb/hr:

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d' (ll.'34 x .0~6] U + 34.0) percent 1

of rated neutron flux whtn total ,

peaking factors in all fuel types are Icss than or equal to those in Specifi-cation 2.1.A.,1, or,

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. The lowest value of:

- Pr I 5 ([1.3'4 x 10-6] W + 34.0)

_ I PFo, 3 percent of rated neutron flux frc=

among those calculaticns for cach fuel type with total peaking factors, PF > Pro , where Pro = peaking factor in

Specification 2.1.A.l.

For recirculation ' flow, W>61 'x 106 lb/hr:

i 115.7 percent of rated neutron flux when total peakinr, factors in all fuel types cre less ther or equal to those in Specification 2.1.A.1,' or The lowest value of < 115.7 I PF o

PF } percent-f .

of rated neutrea flux from among those f

calculatior.s for each fuel type with total pcching factors PF > PF , where PFo=peakingfactorinSpeci!ication 2.1.A.1. .

, b) IRM 138.4 percent of rated neutron flux

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8309080240 PDR ADOCK 050002g 030902 ,

P Amendnent No. 16

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LTvrIn:g sunT 515I1x st.nLG5

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,, nTNCIION -

P.825 psig (initiated in IPJ4

7) Lov Pressure hain Stecm Line, range 10)

P.517 Closure 510 Yal<e Closure frc= full

8) Main Stean Lbe Isolation Yalve oPc3 -

Closure, Scram Reactor Lov Water Level, Scran .

E11',5" above the top of the

9) active fuel as indicated under nor=al operating canditic-E 7 ',2" above the top of the

10) kcactor Low-Lov hter Level,

• active fuel as indicated under F.ain* S'tcan Line Isolation Valve ne:=al operating conditions.

. Cicsure.

t 7'2" above the top of the

11) Reactor Low-Lov Vater Level, active fuel.

Core Spray Initiation i: 7'2" above the top of the

12) Reactor Low-Lov Vater Level, active fuel with time delay Isolation Condenser Initiation 6 3 seconds.

10 percent turbine stop valve (:

13) Turbine Trip Scram closure frca full open.

Ini:iate upon loss of oil

14) Generator Load Rej ection Sera =

pressure fron turbine acceleration relay.

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s 3 ASIS: Saf ety li=its have begn established ,in Specifications 2.1. and 2.2 to protect the integrity of the fuel cladding and reactor coolant

'. system barriers. Automatic protective devices have been provided

• . in the plant design to take corrective action to prevent the safety linics from being exceeded in nomal operation or operational cransients caused by reasonable expectzd single operator error or equipment =alfunction. This Specification establishes the trip set-dngs for these auto =atic protection devices. ,

The. Average Power F.ange Monitor, MP3 , trip setting has been established to assure never reaching the / fuel cladding integrity safery 11:i:. ~~ne MRF. systec :espends ce changes in neu:ren flur.

Eevever, near rated ther:a1 power the A???. is . calibrated, using a

. plant heat balance, so that the neutren For flux slov that is sensed is read

=aneuvers, those out as percent of rated ther=al power.

r where core ther=al power, surf ace heat flux, and the power transferred to the water follow the neutron flux, the MEM will read reactor ther=al power. For fast transients , the neutren flux vill lead the power i

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transf e red from the cladding to the varer due to the effect of the fuel time constan:.

Theref ore, when the neutron flux increases to the scra= setting, the percen: increase in heat increase fir. and power transferred in neutron flu:g.

to tine varer vill be less than the percent The A?EM rip se::ing vill be varied autocarica117 6"I*h **Ci C"18 iC flov vi h the trip setting at rated flou 61.03.ased x 10 en lb/hr or a ec=plete greater being 113.7% of rated neutron flun. .

2.3-3 knendmen't No. M ,39

2.3-5 For operation in the Startup node while the reactor is at low pressure, the IRM range 9 High Flux scram setting of 12% of the rated power provides adequate thermal margin between the maximum power and the safety limit of 18.3% of rated power to acwntodate anticipated maneuvers associated with power plant startup. There are a few possible sources of rapid reactivity input to the system in the low power / low flow condition. Effects of increasing pressure at zero or low void content are minor, because cold water from sources available during the startup is not nuch colder than that already in the system, temperature coefficients are small, and control rod sequences are constrained by operating procedures backed up by the rod worth minimizer. Worth of individual rods is very low in a constrained rod pattern. In a sequenced rod withdrawal approach to the scram level, the rate of power rise is no nore than five percent of the rated per minute, and the IRM system would be note than adequate to assure a scram before the power could exceed the safety limit.

To continue operation beyond 12% of rated power, the IRMs must be transferred into range 10. The Reactor Protection System is designed such that reactor pressure must be above 825 psig to successfully transfer the IRMs into range 10, thus assuring protection for the fuel cladding safety limit. The IRM scram remains active until the node switch is placed in the RUN position at which tine the trip becones a coincident IRM upscale, APRM downscale scram.

The adequacy of the IRM scram was determined by comparing the scran level on the IRM range 10 to the scram level on the APRMs at 30% of rated flow. The IRM scram is at 38.4% of rated power while the APRM scram is at 52.7% of rated power. The mininum flow for Oyster Creek is at 30% of rated power and this would be the lowest APRM scram point. The increased recirculation flow to 65% of flow will provide additional margin to CPR limits. The APRM scram at 65% of rate flow is 87.1% of rated power, while the IRM range 10 scram remains at 38.4% of rated power.

Therefore, transients requiring a scram based on flux excursion will be terminated sooner with a IRM range 10 scram then with an APRM scram. The ,

transients requring a scram by nuclear instrumentation are the loss of I feedwater heating and the improper startup of an idle recirc loop. The loss of feedwater heating transient is not affected by the range 10 IRM since the feedwater heaters will not be put into service until after the LPRM downscales have cleared, thus insuring the operability of the APRM system. This will be administratively controlled. The improper startup of an idle recirc loop becones less severe at lower power level and the IRM scram would be adequate to terminate the flux excursion.

The Rod Worth Minimizer is not required beyond 10% of rated power. The ability of the IRMs to terminate a rod withdrawal transient is limited due to the nunber and location of IRM detectors. An evaluation was performed that showed by maintaining a mininum recirculation flow of 39.65x106 lb/hr in range 10 a couplete rod withdrawal initiated at 35%

of rated power or less would not result in violating the fuel cladding safety limit. Therefore, a rod block on the IRMs at less than 35% of rated power would be adequate protection against a rod withdrawal transient.

2.3-6 The reactor coolant system safety valves offer yet another protective feature for the reactor coolant system pressure safety limit since these valves are sized assuming no credit for other pressere relieving devices. In compliance with Section I of the ASME Boiler and Pressure Vessel Code, the safety valves must be set to open at a pressure no higher than 103% of design pressure, and they must limit the reactor pressure to no more than 110% of design pressure. The safety valves are sized according to the code for a condition of turbine stop valve closure while operating at 1930 MW(t),

followed by (1) a delay of all scrams, (2) failure of the turbine bypass valves to open, and (3) failure of the isolation condensers and relief valves to operate. Under these conditions, a total of 16 safety valves are required to turn the pressure transient. For analysis purposes, the void reactivity coefficient was also pessimistically increased by 50%, i.e.,

a void coefficient 1.5 times normal. With the safety valves set as specified herein the maximum vessel pressure (at the bottom of the pressure vessel) would be about 1301 psig (9);

maximum pressure at the lowest point in the recirculation loop is approximately 1315 psig which is 60 psi below the safety limit. The ASME B&PV Code allows a 11% of working pressure (1250 psig) variation in the pop point of the valves.

This variation is recognized in Specification 4.3.

The low pressure isolation of the main steam lines at 825 psig was provided to give protection against fast reactor depressuri-zation and the resulting rapid cool-down of the vessel.

Advantage was taken of the scram feature which 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 825 psig requires that the reactor mode switch be in the startup position and the IRMs be in the range 9, or lower, where protection of the fuel cladding integrity safety limit is provided by the IRM high neutron flux scram. Thus, the combination of the main steam line low pressure isolation and isolation valve closure scram assures the availability of neutron flux scram protection over the entire range of appli-cability of the fuel cladding integrity safety limit. In addition the isolation valve closure scram anticipates the pressure and flux transients which occur during normal or inadvertent isolation valve closure.

With the scrams set at 10% valve closure, there is no increase in neutron flux and the peak pressure is limited to 1110 psig (9).

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• I ") .1 -11 .

TAlli.E 3.1.1 PROTECTIVE I;ISTRIT!!E!4TATIOld ILEQUIHDIEllTS (CO4TD)

Min. 110. of Plin. tio . of Operable Reactor flodes Docrable or Instrument in Wlitcli Function Operating Cliannels Per linst fle Opernble (Tr ipped) Trip Operable Action Sliutdown Refuel Startup thin Syntems Trip Syntens  !!esintreda Funct lun Trip Settiny, Close sonin atcata 11 lions:t or inulus ton toolation valves AA X 'X X X 2 2 and clone isold-

1. I.uw-l.w itenctor tion condenner IJnte r f.evel vent valven, os' 2 2 place in cold 3 120%' rated X (5) X (s) X X

2. liigli Flow in shutdown condi-lin in S t e nm-

• tion line A 2 2 7.fs) X (s) X X

3. liigh Flow in 3 120% rated linin Steam-line B 2 2 X (s) X (s) X X

4. Illgh Terapera- 3 mbient A at ture in tinin Power + $0"F , .

S t e niallne ,

Tunnel 2 2 AA X(cc) X

5. 1.uw Preuunro in !!.iln Stenm-line X 2 2 (i . Illgh linillnl lon- 3 10X Horinni X'(s) X(s) X in finin Steaun auckstunnd -.. _ = - _ -

Tunnel .

6. I nni ni lim (*undesirii? r 2 2 l'laca p'ont in AA X ( te) X(n) X X

1. Illgh itenctor cold ohutdokn P resinure condition X 2 2 X(s) X(s) X

7. l.ow-l. ins itenctor  ?. 7' 2" nhove w - - - -

nme mit

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3.1-14

. TADI.l! 3.1.1 (Cont'd)

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v. Thaya functions not reyntred to be operable when the /.DS is not required to be operablo. -

w. These functions must bo operahlo only when irradiated fuol is in the fuol pool or reactor vossol -

and secondary containment integrity is required por spocification 3.5.11 .

y. The number of operable channels may be reduced to 2 por Spect'fication 3.9-I! and F. .

z. The bypass function to permit scram 'rcset in the shutdown or rc{uel mode with control rod '

biopk must he opernble in this mode. '

an. Pump circuit breakers will be tripped in lo ieconds 115% during a IDC4 by relays SK7A and SXSA.

bb. Pump circul't breakers will trip lustantaneously during a IDCA. .

cc. Only applicable during STARTUP Mode while operating in IRM Range 10.

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. Amen &ient No. A4~ g 63

l 3.3-2a C. Primary Coolant System Pressure Isolation Valves Applicability:

Operational Conditions - Startup and Run Modes; applies to the operational status of the primary coolant system pressure isolation valve s.

Objective:

To increase the reliability of primary coolant system pressure isolation valves thereby reducing the potential of an intersystem loss of coolant accident.

Specification:

1. During reactor power operating conditions, the integrity of all pressure isolation valves listed in Table 3.3.1 shall be demonstrated. Valve leakage shall not exceed the amounts indicated.

2. If Specification 1 cannot be met, an orderly shutdown shall be initiated and the reactor shall be in the cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

H. Required Minimum Recirculation Flow Rate

1. A minimum recirculation flow rate is required to insure that technical specification transient MCPR limits for operation are not exceeded.

2. An analysis should be performed to insure the applicability of the flow rate in Specification 3.3.H.3 for each reload.

3. 39.65x10 6 lb/hr is the minimum recirculation flow rate necessary for STARTUP at this time. This flow rate leaves sufficient margin between minimum flow required by the RWE analysis performed and the minimum flow used in STARIUP.

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4.1-4 The logic of the instrument safety systems in Table 4.1.1 is such that testing the instrument channels also trips the trip system, verifying that it is operable. However, certain systems require coincident instrument channel trips to completely test their trip systems. Therefore, Table 4.1.2 specifies the minimum trip system test frequency for these tripped systems. This assures that all trip systems for protective instrumentation are adequately tested, f rom sensors through the trip system.

Every element of electrical circuitry for the reactor protection system is to 1

be verified operable prior to plant startup by functional testing. Parallel

, elements of circuits which do not permit functional verification of freedom i f rom shorts by routine channel trips are to be verified functional during refueling shutdown.

IRM calibration is to be performed during reactor startup. The calibration of the IRMs during startup will be significant since the IRMs will be relied on

, for neutron monitoring and reactor protection up to 33.4% of rated power j during a reactor startup.

References:

(1) " Reliability of Engineered Safety Features as a Function of Testing Frequency," I. M. Jacobs, Nuclear Safety, Volume 9, No. 4, July-August ,1968.

(2). " Reactor Protection System, A Reliability Analysis,"

I. M. Jacobs, APED-5179, Eng. A-16, June,1966.

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Instrument Channel Check Calibrate Tes t Remarks (Applies to Test and Calibration)

APRM Scram Trips

• Note 2 1/wk 1/wk Using built-in calibration equipment during power operation

12. APRM Rod Blocks Note 2 1/3 mo 1/mo Upscale and downscale

13. a. liigh Radiation on Main 1/s 1/3 mo '/wk l Using built-in calibration equipment Steamline during power operation

b. Sensors for 13(a) NA Each Refueling NA Using external radiation source Outage 14 . High Radiation in Reactor Building Operating Floor 1/s 1/3 mo. 1/wk. Using gamma source for calibration Ventilation Exhaust 1/s 1/3 mo. 1/wk Using gamma source for calibration

15. High Radiation on Air 1/s 1/3 mo 1/wk. Using built-in calibration equipment Ejector Of f-Gas

16. IRM Level NA , Each Startup NA IRM Scram * *

• Using built-in claibration equipment

17. IRM Blocks NA Prior to Prior to Upscale and downscale Startup and startup and Shutdown Shutdown

18. Condenser Low Vacuum NA Each Refuel- Each Refuel- -

ing outage ing outage

• Calibrate prior to startup and normal shutdown and thereaf ter check 1/s and test 1/wk until no longer required.

Irgend: N A = Not applicable; .1/8 = Once per shif t; 1/d = Once per day; 1/3d = Once per 3 days; 1/wk = Once per week; 1/3 mo = Once every 3 months.

N N