ML20101E002
| ML20101E002 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 12/05/1984 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML20101E004 | List: |
| References | |
| NUDOCS 8412260098 | |
| Download: ML20101E002 (5) | |
Text
'.!ST OF TA3LIS Tab le "o.
Pace 3.1.1 Rese:or Prote :1on System (Scram) Instru=en: Requiremen:s 23
~
4.1.1 Scras Ins::unent Func:ional Tests - Minimum Functional 32 Iest Frequencies for Safety Instrunents:1on and Control Circuits 4.1.2*
Scram Instrument Calibration - M'"d-"2 Calibra: ion 34 Frequencies for Rez'!ar ? stection Instrument Channels 3.2.1 Ins :umentation tha: Int iates Pri=ary Containment 49 Isolation Functions
3.2.2 Instruments
ion tha Initiates !=ergency Core Cooling Syste=s 32 3.2.3 Ins:::=en ation that Initiates Red 31ock 57 3.2.4 Instrumentation that Ini:iates Reactor 3uilding 7entilation 59 Isolation and Standby Cas Treatment System Initia:1on 3.2.5 Ins::umentation that Ini:iates a Recircula-don Pump Trip 60 3.2.6 Instrumenta. ion for Safeguards 3us Degraded Voltage and 60a Loss of Voltage ? otection 3.2.7 Instrumentation for Safety / Relief Valve Low-Low Set Logic 60b 4.2.1 Mi - d -im Test and Calibration Frequency for Core Cooling, Rod 31ock and Isolation Instru=entaticn 61 3.6.1 Safety Related Snubbers 13 1 3.7.1
?-i=arr Contain=en: Isolation 172 3.3.1 Radioactive Liquid Iffluent Monitoring Ins::u=en:2:1on 1891 3.S.2 Radioactive Gaseous Ifflues: Monitoring Ins :u=entatics 198k 4.3.1 Radioac:1ve Liquid Iffluent :!onitoring Ins :a=ents: ion 19Es Surveillance Requirements 4.3.2 Radioactive caseous !!fluen: NnitoringIns:::=ents:1on 195n Surveillance Requirements 4.3.3 Radioac:ive Licuid Uaste Samsling and Analysis ?:og:sm 199 4.3.4 Radioactive Caseous Uaste Sa.pl1=g and Analysis ?:ogram 193s
- 3. u.1 Mand-
- average ? lana: '.inear Rea: Genera:1on Ra:e 215
- / s. Inposure 2.10.1 Saf ety telsted Tire 7e:c:-:.on : s: u-en:s 8412260098 841205 Amendment No. J9', 30 PDR ADOCK 05000263 p
Bases continued:
3.2 increases core voiding, a negative reactivity feedback.. High pressure sensors initiate the pump trip in the event of an isolation transient. Low level sensors initiate the trip on loss of feedwater (and the resulting MSIV closure). The recirculation pump trip is only required at high reactor power levels, where the safety / relief valves have insufficient capacity to relieve the steam which continues to be generated after reactor isolation in this unlikely postulated event, requiring the trip to be operable only when'in the RUN mode is therefore conservative.
Voltage sensing relays are provided on the safeguards bus to transfer the bus to an alternate source when a loss of voltage condition or a degraded voltage condition is sensed.
On loss of voltage this transfer occurs immediately.
The transfer on degraded voltage has a. time delay to prevent transfer during the starting of large loads. The degraded voltage setpoint corresponds to the minimum acceptable safeguards bus voltage for starting and running loads during a loss of coolant accident. An allowance for relay tolerance is included.
Safety / relief valve low-low set logic is provided to prevent any safety / relief valve from opening when there is a elevated water leg in the respective discharge line. A high water 103 is formed immediately following valve closure due to the vacuum formed when steam condenses in the line.
If the valve reopens before the discharge line vacuum breakers act to return water level to normal, water clearing thrust loads on the discharge line may exceed their design limit.
The logic reduces the opening setpoint and increases the blowdown range of three non-APRS valves following a scram. A 15-second interval between subsequent valve actuations is provided assuming one valve fails to N
8e O
y; 3.2 BASES 69 S
naues cuntinued:
open and instrumentation drift has caused the nominal 80-psi. blowdown range to be reduced to 60 psi.
Maximum water leg clearing time has been calculated to be less than 6 seconds for the Monticello design.
Inhibit timers are provided for each valve to prevent the valve from being manually opened less than 10 seconds following valve closure.
Valve opening is sensed by pressure switches in the valve discharge line.
Each valve is provided with two trip, or actuation, systems. Each system is provided with two channels of instrumentation for each of the above described functions. A two-out-of-logic scheme ensures that no single' failure will defeat the low-low set two-once function and no single failure will cause spurious operation of a safety / relief-valve.
Allowable deviations are provided for each specified instrument setpoint. Setpoints within the specified allowable deviations provide assurance that subsequent safety / relief valve actuations are suf ficiently spaced to allow for discharge line water le's clearing.
Although the operator will set the set points within the trip settings specified in Tables 3.2.1 through 3.2.1, the actual values of the various set points can differ appreciably from the value the operator is attempting to set.
The ouviations could be caused by inherent lustrument error, drif t of the set point, ect.
Therefore, these deviations have been accounted for in the various transient analyses and the actual trip settings may vary by the following amounts:
ff
References:
l 3
k 1.
" Average Power Range Monitor, Rod Block Monitor and Technical Specifications Improvement (ARTS) g Program for Monticello Nuclear Generating Plant", NEDC-30492-P, April, 1984.
EI 1
'). 2 IlA!;E i l
69a l
l l
i
Trip Functlon Deviatlon Instrumentation Tliat Initiates Emergericy 1.ow-1.ow Reactor llater Level
-3 Incties
(:oi e (:im i I nt; Sys t ems Talil e 3.2.2 Reactor Low Pressure (Pump
-10 psi Start) Permissive liigli Drywell Pressure
+1 psi Low Reactor Pressure (Valvo
-10 pst Permissive)
In:i s rumenta t ton Tlia t Inttintes IRH 110wnscale
-2/125 of Scato no.1 ulock Ilot lipscale 12/125 of Scale Talile 3.2.3.
APHil Downscale
-2/125 of Scale APIUI tipscale See Basis 3.2 RilH Ilownscale
-2/125 of Seale RBil lipucale
+2/125 of Scale Scram 111scliarge Volume-liigli
+ 1 gallon Level In:s t rumenta t ion Tlia t Initiaten Illgli Reactor Pressure
+ 12 pat x
itecirculation Pump Trip Low Reactor llater Level
-3 Inclies 5
y k
Instrumentation for Safeguards Degraded Voltage
>3897 volts (trip) g Bus Protection
<3975 volts (reset)
=
2
>5 see <10 see (delay) w Loss of Voltage
<3000 volts >2000 volts 3
i..> nas el 71
e e
Trip Function.
Deviation Instrumentation for Safety / Relief Valve Reactor Coolant System 120 psig.-
Low Low Set Logic Pressure for Opening /Closin'g-Opening - Closing Pressure
>t 3 psi Discharge Pipe Pressure 110 psid Inhibit Timer Inhibit
-3 sec
+10 see
. A violation of this specification is assumed to occur only when a device is knowingly set outside of the limiting trip settings, or, when a suf ficient number of devices have been affected by any means such that the automatic function is incapable of operating within the allowable deviation while in a reactor mode in g
which the specified function must be operable or when actions specified are not initiated as specified.
3.2 BASES 71a
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