ML022250071
| ML022250071 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 08/09/2002 |
| From: | NRC/NRR/DLPM/LPD2 |
| To: | Southern Nuclear Operating Co |
| References | |
| TAC MB3568, TAC MB3569 | |
| Download: ML022250071 (11) | |
Text
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'EC'= ---DCE __Ra - ,. "',A TRIP zUNCTION COND,70NQ %N* L-ST 22'C -.
C-A\\E- E _.E-S AWE ON 17T Reactor Tnp 1. ra:ns 7 SR 3-32 NA NA Breakers(k) 3ca*, 4a2,, :z:a) 2:rains C SR ,.3. NA NA 18 Reactor Trip 1,2 leach per UV SR 3.3.14 NA NA Breaker RTB Undervoltage and Shunt Trip 31a) 4(a), 5a, I each per C SR 3.3.1.4 NA NA Mechanisms RTB 19 Aucomabc Tnp :,2 2 trains 0.V SR 3.3,1.5 NA NA Logic 3 (a) 4(a, 5(a) 2 trains C SR 3.3.1.5 NA NA (a) With RTBs closed and Rod Control System capable of rod withdrawal.
(k) Including any reactor trip bypass breakers that are racked in and closed for bypassing an RTB.
(n) A channel is OPERABLE with an actual Trip Setpoint value outside its calibration tolerance band provided the Trip Setpoint value is conservative with respect to its associated Allowable Value and the channel is readjuSted to within the established calibration tolerance band of the Nominal Trip Setpoint. A Tnp Setpoint may be set more conservative than the Nominal Trip Setpoint as necessary in response to plant conditions.
Vogtle Units 1 and 2 3.3.1-19 Amendment No. 101 (Unit 1)
Amendment No. 79 (Unit 2)
RTS Instrumentation 3.3.1 Table 3.3.1-1 (page 7 of 8)
Reactor Trip System Instrumentation Note 1: Overtemperature Delta-T following shall not exceed the Nominal Trip Setpoint defined by the The Overtemperature Delta-T Function Allowable Value equation by more than 2.25% of RTP.
[ T4S)0 + '6 s) . T'] -K3{P' - P} - fl(AFD)
AT 0 G1++ T12 ss) {+ !+K2 AT T3 s)l0+ -r5s}L F
Where: AT measured loop specific RCS differential temperature, degrees F
ATO indicated loop specific RCS differential at RTP, degrees temperature 1+¶[S lead-lag compensator on measured differential 1+'12s temperature: r, > 8 seconds, Tj, =2 time constants utilized in lead-lag compensator for differential T2 5 3 seconds 1+.1s lag compensator on measured differential temperature temperature, :5 2 seconds
'13 time constant utilized in lag compensator for differential Ki fundamental setpoint, < 112% RTP K2 modifier for temperature, = 2.24% RTP per degree F 1+-ss lead-lag compensator on dynamic temperature compensation temperature compensation: '14 k 28 seconds, T4, 15 time constants utilized in lead-lag compensator for T s5 4 seconds degrees F T measured loop specific RCS average temperature, I._
l+%as lag compensator on measured average temperature
= 0 seconds time constant utilized in lag compensator for average temperature, RTP, <588.4 degrees F T, indicated loop specific RCS average temperature at K3 modifier for pressure, = 0.115% RTP per psig P measured RCS pressurizer pressure, pslg p reference pressure, k 2235 psig s Laplace transform variable, inverse seconds f,(AFD) modifier for Axial Flux Difference (AFD):
- 2. for each % AFD is below -23%, the trip setpoint shall be be reduced by 1.95% RTP
- 3. for each % AFD is above +10%, the trip setpoint shall 3.3.1-20 Amendment No. 127 (Unit 1)
Vogtle Units 1 and 2 Amendment No. 105 (Unit 2)
RTS Instrumentation 3.3.1 Table 3.3.1-1 (page 8 of 8)
Reactor Trip System Instrumentation Note 1: Overtemperature Delta-I (continued)
(o) The compensated temperature difference T -1 shall be no more negative than 3 degrees F.
{I + T5 ) 10+ 6 s)
Note 2: Overpower Delta-"
defined by the following equation The Overpower Delta-T Function ALLOWABLE VALUE shall not exceed the Nominal Trip Setpoint by more than 2.85% of RTP.
1+rs) 1 AT0 (1 + T2 s) (Il+r3s).
] K4 [}
K I 1
+r 8)
{1+s)
-KL (T *
.s.)
Where: AT measured loop specific RCS differential temperature, degrees F ATO Indicated loop specific RCS differential at RTP, degrees F 1 lead-lag compensator on measured differential temperature
,* time constants utilized In lead-lag compensator for differential temperature: T1 2 8 seconds,
-;2: 3 seconds 1- rTss lag compensator on measured differential temperature 3 time constant utilized in lag compensator for differential temperature, 5 2 seconds K4 fundamental setpoint, < 109.5% RTP Ks modifier for temperature change: a 2% RTP per degree F for increasing temperature, k 0% RTP per degree F for decreasing temperature 1-+Ts rate-lag compensator on dynamic temperature compensation time constant utilized In rate-lag compensator for temperature compensation, > 10 seconds T measured loop specific RCS average temperature, degrees F
_.1_
lag compensator on measured average temperature
%B time constant utilized in lag compensator for average temperature, = 0 seconds 14 modifier for temperature: k 0.20% RTP per degree F for T > T"1,= 0% RTP for T <T1 "rT indicated loop specific FICS average temperature at RTP, < 588.4 degrees F 3 Laplace transform variable. Inverse seconds f2(AFD) modifier for Axial Flux Difference (AFD). = 0% RTP for all AFD Vogtle Units 1 and 2 3.3.1-21 Amendment No. 127 (Unit 1)
Amendment No. 105 (Unit 2)
RTS Instrumentation B 3.3.1 BASES APPLICABLE 6. Overtemperature AT (continued)
SAFETY ANALYSES, LCO, and has the same effect on AT as a power increase. The APPLICABILITY Overtemperature AT trip Function uses each loop's AT as a measure of reactor power and is compared with a setpoint that is automatically varied with the following parameters:
" reactor coolant average temperature - the Trip Setpoint is varied to correct for changes in coolant density and specific heat capacity with changes in coolant temperature;
"* pressurizer pressure - the Trip Setpoint is varied to correct for changes in system pressure; and
" axial power distribution - f(AFD)x, the f(AFD) Function is used in the calculation of the Overtemperature AT trip. It is a function of the indicated difference between the upper and lower NIS power range detectors. This Function measures the axial power distribution. The Overtemperature AT Trip Setpoint is varied to account for imbalances in the axial power distribution as detected by the NIS upper and lower power range detectors. If axial peaks are greater than the design limit, as indicated by the difference between the upper and lower NIS power range detectors, the Trip Setpoint is reduced in accordance with Note 1 of Table 3.3.1-1.
Dynamic compensation is included for RTD response time delays.
The Overtemperature AT trip Function is calculated for each loop as described in Note 1 of Table 3.3.1-1. A trip occurs if Overtemperature AT is indicated in two loops. Since the pressure and temperature signals are used for other control functions, the actuation logic must be able to withstand an input failure to the control system, which may then require the protection function actuation, and a single failure in the other channels providing the protection function actuation.
(continued)
Vogtle Units 1 and 2 B 3.3.1-17 Rev. 1 - 8/02
BASES APPLICABLE 6. Overtemperature _ýT (continued)
SAFETY ANALYSES. 7.2.2.3 of LCO, and This results in a two-out-of-four trip logic. Section system APPLICABILITY Reference 1 discusses control and protection that this Function also interactions for this function. Note prior to reaching provides a signal to generate a turbine runback turbine power the Trip Setpoint. A turbine runback will reduce alleviate and reactor power. A reduction in power will normally a reactor the Overtemperature AT condition and may prevent trip.
overpower AT Delta-To, as used in the overtemperature and each trips, represents the 100% RTP value as measured for actual loop. This normalizes each loop's AT trips to the time of measurement, thus o.perating conditions existing at the as power conditions forcing the trip to reflect the equivalent full in RCS assumed in the accident analyses. These differences differences in RCS loop AT can be due to several factors, e.g.,
between loop flows and slightly asymmetric power distributions change expected to quadrants. While RCS loop flows are not quadrants with cycle life, radial power redistribution between specific AT values.
may occur, resulting in small changes in loop as needed to Therefore, loop specific ATo values are measured ensure they represent actual core conditions.
since it defines The parameter K1 is the principal setpoint gain, K and K define the the function offset. The parameters 2 3 The values temperature gain and pressure gain, respectively.
for T and P' are key reference parameters corresponding assumptions directly to plant safety analyses initial conditions of AT function. For the purposes for the Overtemperature K,
performing a CHANNEL CALIBRATION, the values for Ki, 2 without explicit K3 , T, and P' are utilized in the safety analyses values for tolerances, but should be considered as nominal setting is not instrument settings. That is, while an exact is desired.
expected, a setting as close as reasonably possible be set hottest RCS loop will Note that for T, the value for the (continued) b....- 10 Rev. 1-6/98 b , I.3
- 10 Vogtle Units 1 and 2
RTS Instrumentation B 3.3.1 BASES APPLICABLE 6. Overtemperature AT (continued)
SAFETY ANALYSES, LCO, and as close as possible to 588.40 F. The value of T' for the APPLICABLITY remaining RCS loops will be set appropriately less than 588.40 F based on the actual loop specific indicated T=,,.
In the case of decreasing temperature, the compensated temperature difference shall be no more negative than 3 OF to limit the increase in the setpoint during cooldown transients.
The engineering scaling calculations use each of the referenced parameters as an exact gain or reference value.
Tolerances are not applied to the individual gain or reference parameters. Tolerances are applied to each calibration module and the overall string calibration. In order to ensure that the Overtemperature AT setpoint is consistent with the assumptions of the safety analyses, it is necessary to verify during the CHANNEL OPERATIONAL TEST that the Overtemperature AT setpoint is within the appropriate calibration tolerances for the defined calibration conditions (Ref. 9).
The LCO requires all four channels of the Overtemperature AT trip Function to be OPERABLE. Note that the Overtemperature AT Function receives input from channels shared with other RTS Functions. Failures that affect multiple Functions require entry into the Conditions applicable to all affected Functions.
In MODE 1 or 2, the Overtemperature AT trip must be OPERABLE to prevent DNB. In MODE 3,4, 5, or 6, this trip Function does nut have to be OPERABLE because the reactor is not operating and there is insufficient heat production to be concerned about DNB.
(continued)
Vogtle Units 1 pnd 2 B 3.3.1-19 Rev. 2-8/02
BASES
- 7. Overpower AT APPLICABLE SAFETY ANALYSES, B, TDI-0421 B.
LCO, and The Overpower Ž_T trip Function (TDI-041 1 TDI-0431A, APPLICABILITY TDI-0431 B, TDI-0441B, TDI-041 1A, TDI-0421A.
to ensure the (continued) TDI-0441A) ensures that protection is provided and less than 1%
integrity of the fuel (i.e., no fuel pellet melting conditions. This trip cladding strain) under all possible overpower of the Overtemperature Function also limits the required range Power Range AT trip Function and provides a backup to the AT trip Neutron Flux - High Setpoint trip. The Overpower rate (kW/ft)
Function ensures that the allowable heat generation of each loop as a of the fuel is not exceeded. It uses the AT is automatically measure of reactor power with a setpoint that varied with the following parameters:
Setpoint is reactor coolant average temperature - the Trip density and specific varied to correct for changes in coolant and heat capacity with changes in coolant temperature; rate of change of reactor coolant average temperature response time including dynamic compensation for RTD delays.
for each loop as The Overpower AT trip Function is calculated AT is per Note 2 of Table 3.3.1-1. Trip occurs if Overpower signals are used indicated in two loops. Since the temperature must be able to for other control functions, the actuation logic which may then withstand an input failure to the control system, a single failure in require the protection function actuation and function the remaining channels providing the protection trip logic. Section actuation. This results in a two-out-of-four protection system 7.2.2.3 of Reference 1 discusses control and Function also interactions for this function. Note that this prior to reaching provides a signal to generate a turbine runback will reduce turbine the Allowable Value. A turbine runback in power will normally power and reactor power. A reduction may prevent a reactor alleviate the Overpower AT condition and trip.
(continued) 4 on Revision No. 0 Vogtle Units 1 and 2 D a.-0. l-..
RTS Instrumentation B 3.3.1 BASES SURVEILLANCE SR 3.3.1.15 (continued)
REQUIREMENTS Response time may be verified by actual response time tests in any series of sequential, overlapping, or total channel measurements; or by the summation of allocation sensor, signal processing, and actuation logic response times with actual response time tests on the remainder of the channel. Allocations for sensor response times may be obtained from: (1) historical records based on acceptable resonse time tests (hydraulic, noise, or power interrupt tests), (2) in place, onsite, or offsite (e.g.,
vendor) test measurements, or (3) using vendor engineering specifications. WCAP-13632-P-A Revision 2, "Elimination of Pressure Sensor Response Time Testing Requirements,"
(Ref. 10), provides the basis and methodology for using allocated sensor response times in the overall verification of the channel response time for specific sensors identified in the WCAP.
Response time verification for other sensor types must be demonstrated by test.
WCAP-14036-P Revision 1, "Elimination of Periodic Protection Channel Response Time Tests," (Ref. 11), provides the basis and methodology for using allocated signal processing and actuation logic response times in the overall verification of the protection system channel response time. The allocations fc- sensor, signal conditioning and actuation logic response times must be verified prior to placing the component in operational service and re verified following maintenance that may adversely affect response time. In general, electrical repair work does not impact response time provided the parts used for repair are of the same type and value. Specific components identified in the WCAP may be replaced without verification testing. One example where response time could be affected is replacing the sensing assembly of a transmitter.
As appropriate, each channel's response must be verified every 18 months on a STAGGERED TEST BASIS. Testing of the final actuation devices is included in the testing. Response times cannot be determined during unit operation because equipment operation is required to measure response (continued)
B 3.3.1-63 Rev. 3-8/02 Vogtle Units I and 2
BASES BASES SURVEILLANCE SR 33.1.15 icontinuedý REQUIREMENTS times. Experience has shcwn that these components usually pass this surveillance when performed at the 18 month Frequency. Therefore. the Frequency was concluded to be acceptable from a reliability standpoint.
SR 3.3.1.15 is modified by a Note stating that neutron detectors are excluded from RTS RESPONSE TIME testing. This Note is necessary because of the difficulty in generating an appropriate detector input signal. Excluding the detectors is acceptable because the principles of detector operation ensure a virtually instantaneous response.
SR 3.3.1.16 SR 3.3.1.16 is the performance of a COT for the low fluid oil pressure portion of the Turbine Trip Functions as described in SR 3.3.1.7 except that the Frequency is after each entry into MODE 3 for a unit shutdown and prior to exceeding the P-9 interlock trip setpoint. The surveillance is modified by two Notes. Note 1 states that the surveillance may be satisfied if performed within the previous 31 days. Note 2 states that verification of the setpoint is not required. The Frequency ensures that the turbine trip on low fluid oil pressure channels is OPERABLE after each unit shutdown and prior to entering the Mode of Applicability (above the P-9 power range neutron flux interlock) for this instrument function.
REFERENCES 1. FSAR, Chapter 7.
(continued)
B 3.3.1-64 Rev. 1-3/99 Vogtle Units 1 and 2
RTS Instrumentation B 3.3.1 BASES REFERENCES 2. FSAR, Chapter 6.
(continued) 3. FSAR, Chapter 15.
- 4. IEEE-279-1971.
- 5. 10 CFR 50.49.
- 6. WCAP-1 1269, Westinghouse Setpoint Methodology for Protection Systems; as supplemented by:
Amendments 34 (Unit 1) and 14 (Unit 2), RTS Steam Generator Water Level - Low Low, ESFAS Turbine Trip and Feedwater Isolation SG Water Level - High High, and ESFAS AFW SG Water Level - Low Low.
Amendments 48 and 49 (Unit 1) and Amendments 27 and 28 (Unit 2), deletion of RTS Power Range Neutron Flux High Negative Rate Trip.
" Amendments 60 (Unit 1) and 39 (Unit 2), RTS Overtemperature AT setpoint revision.
" Amendments 57 (Unit 1) and 36 (Unit 2), RTS Overtemperature and Overpower AT time constants and Overtemperature AT setpoint.
" Amendments 43 and 44 (Unit 1) and 23 and 24 (Unit 2),
revised Overtemperature and Overpower AT trip setpoints and allowable values.
" Amendments 104 (Unit 1) and 82 (Unit 2), revised RTS Intermediate Range Neutron Flux, Source Range Neutron Flux, and P-6 trip setpoints and allowable values.
" Amendments _ (Unit 1) and _ (Unit 2), revised Overtemperature AT trip setpoint to limit value of the compensated temperature difference and revised the modifier for axial flux difference.
- 7. WCAP-10271-P-A, Supplement 1, May 1986.
- 8. FSAR, Chapter 16.
- 9. Westinghouse Letter GP-16696, November 5, 1997.
- 10. WCAP-13632-P-A Revision 2, "Elimination of Periodic Sensor Response Time Testing Requirements,m January 1996.
(continued)
B 3.3.1-65 Rev. 4-8/02 Vogtle Units 1 and 2
RTS Instrumentation B 3.3.1 BASES REFERENCES 11. WCAP-14036-P-A Revision 1, "Elimination of Periodic (continued) Protection Channel Response Time Tests," October 1998.
- 12. WCAP-14333-P-A, Rev. 1, October 1998.
- 13. WCAP-10271 -P-A, Supplement 2, Rev. 1, June 1990.
B 3.3.1-66 Rev. 0 -8/02 Vogtle Units 1 and 2