ML20206M515
| ML20206M515 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 08/15/1986 |
| From: | CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | |
| Shared Package | |
| ML20206M505 | List: |
| References | |
| NUDOCS 8608210241 | |
| Download: ML20206M515 (13) | |
Text
...
ATTACHMENT 1 Consumers Power Company Big Rock Point Plant Docket 50-155 i
PROPOSED TECHNICAL SPECIFICATION PAGE CHANGES August 15, 1986 f
f l
8608210241 860815 PDR ADOCK 05000155 P
PDR 6 Pages TSB0786-0125-NLO4
-.. -- - --.-.- -.~..
- -. -- - w
~; -
54 6.1.2.1 Source Range Monitor Channel - Channels 6 and 7 shall provide logarithmic neutron flux level and period information from source level to seven decades above source level, without moving detectors
-10
-3 (approximately 10 to 10 % of rated power). The principal components in each channel shall be a neutron detector, current pulse amplifier, source range monitor instrument, log count rate meter, log count rate recorder and period meter. Gas-filled Boron-10 lined proportional counters with a sensitivity of approximately 12 counts /nv shall be used as detectors. Provisions shall be made for remotely positioning the detectors. By moving the detectors away-from the midplane of the core, their effective range may be extended.
A short period on either channel shall be annunciated in the control room.
6.1.2.2 Intermediate Range Channels - Channels 4 and 5 provide logarithmic
-5 neutron flux level and period information from approximately 10 g g, rated power for the 84-bundle core. The principal components in each channel shall be a neutron detector, dual high-voltage power supply, Log-N and period amplifier, Log-N indicator, period indicator, and Log-N recorder. The detectors shall be gamma compensated ion
-10 chambers with a design sensitivity of at least 2.2 x 10 amperes /nv.
6.1.2.3 Power Ranae Channels'- Channels 1, 2 and 3 shall provide linear
~7 neutron flux level information from approximately 10 % to 125% rated
. power for the 84 fuel bundle core. The principal components in each channel shall be a neutron detector, dual power supply, picoammeter with console range switch and power level indicator, and power level recorder. The detectors shall be gamma compensated ion chambers with
-10 a design sensitivity of at least 2.2 x 10 amperes /nv. The amplifier output shall be connected to the reactor safety system.
l l
6.1.2.4 In-Core Flux Monitors - In-core flux monitors shall be used to I
evaluate predicted power distributions and detect power oscillations or deviations from expected power distributions in time for the j
operator to take corrective action to avoid exceeding local heat flux limits.
6.1.2.5 Neutron Monitoring Range Switch - The range switches are used in conjunction with the flux amplifiers to provide a selection of seven l
ranges of percent power.
The range switches on the three power level instruments contain resistor-capacitor feed-back circuit combinations which can be switched to provide nine decades of overlapping power level indication. The unit also contains interlock contacts used in conjunction with the upscale-downscale trip unics of the l
picoammeters.
Proposed 1
TSB0786-0125-NLO4
58 6.1.5 (Contd)
(c)
Both source range monitor channels shall be OPERABLE and measuring flux from the core during reactor start-ups, prior to the power level at which the intermediate or power range channels become operative. However, if one of the two source range monitor channels become inoperative during the course of start-up and prior to the power level at which the intermediate or power range channels become operative, then it will be permissible to hold the control rod pattern and power level attained until both channels are again OPERABLE.
(d)
There shall be a minimum of two intermediate range channels providing logarithmic neutron flux level information and period scrga protection during reactor start-up from approximately 10- % to approximately 5% of rated power.
For reactor operation above approximately 5% of rated power, the logarithmic neutron flux level information and period scram protection are not required (see Section 6.1.2).
(e)
Any one of the three power range flux monitors may be taken out of service for maintenance during reactor operation. If one monitor is out of service, a trip on either of the two remaining monitors shall scram the reactor. When maintenance is necessary, no major changes in power level, flux j
distribution or the control rod pattern shall be made.
(f)
During POWER OPERATION in-core flux monitors shall be operatinf, to insure that local heat flux limits specified in Section 5.2.1 are not exceeded.
(g)
Protection against a " cold-water accident" is provided by recirculation pumps and valve interlocking. The valves on either side of the recirculating pumps are interlocked with pump power such that each valve must be in its proper position i
before the pump motor can be started.
If the suction valve to the pump is closed, the motor will be tripped. If the discharge valve and bypass valve are closed, the motor will be tripped.
(h)
Minimum nuclear instrumentation in operation during SHUTDOWN i
operation shall be the same as that required for REFUELING OPERATION, except that only one source range monitor channel shall be required.
Proposed i
TSB0736-0125-NLO4
71a 7.3.2 (Contd)
(d) The source range monitor shall indicate a minimum of three counts per second with a signal-to-noise ratio of 3 to 1.
This will be accomplished by withdrawing.the proportional counter to a region of lower flux and observing the reduction in count rate.
In the event that neutron source strength is insufficient to produce the required count rate, an approach to criticality for reactor start-up shall be allowed provided that the following conditions are met:
(i)
Prior to the first start-up after development of the low source strength condition, a critical approach (es) with the reactor vessel head off shall be performed to evaluate the source range monitor response and the control rod withdrawal sequence. Two additional low-level detectors shall be temporarily inserted in the vessel to monitor this head-off critical approach (es). These additional detectors shall indicate a minimum of 3 counts per second with a signal-to-noise ratio of 3 to 1.
(ii)
Evaluation of source range monitor responses during the head-off critical approach (es) shall demonstrate that, by the time the estimated k of the core reaches 0.995, each.sourcerangemonitoIksreadingatleast3cpswitha 3 to 1 signal-to-noise ratio.
(iii)
Critical approaches with the head on and without the temporary in-vessel low-level detectors in service shall be permitted provided that the instrument response requirements qf (ii) above have been demonstrated and provided that these same requirements are also met during each critical approach with the head on.
Normal start-up may continue any time source range monitor count rate is at least 3 counts per second with a minimum signal-to-noise ratio of 3 to 1.
(iv)
The procedure of (i) and (ii) above shall be repeated by conducting an additional head-off critical approach (es) in the event of either a core configuration change or a significant change in that part of the control rod with-drawal sequence for which the minimum count rate and signal-to-noise ratio specified above are not attainable.
(v)
The site reactor engineer or his alternate will be on site during all head-off critical approaches and instrument response evaluations and during the initial head-on start-up following head-off evaluations.
Proposed TSB0786-0125-NLO4 l
1--
-,_. -- - + - -,
,..w,,-.,._,.-_
_r,.,
.,,_.._v-,-,.-,,,,,-,.,,,,,,.,,---.9
72 7.3.2 (Contd)
(e) Critical approaches shall be monitored using source range monitors. The start-up rate shall be restricted to demonstrate that the CIC picosameters overlap the source range monitors at
-5 about 10 % indicated full power on the picoammeters is normal and satisfactory for control and safety purposes before continuing further into the power range. Control rod withdrawal sequence shall be specified and limited to those sequences shown by previous analysis or tests to preserve fuel integrity in the event of accidental reactivity insertion either while starting up or at power.
(f) The power shall be adjusted once criticality is reached to maintain a reactor vessel temperature rise rate not to exceed 100*F per hour.
(g) The turbine shaft sealing system shall be placed in service as soon as sufficient steam pressure is available (approximately 150 psig).
(h) The condenser shall be evacuated with the mechanical vacuum pump and the air ejector will be placed in service.
(1) Turbine heating shall be started during this operation sequence.
After turbine heating is completed, the turbine shall be gradually brought up to speed.
(j) The mode of turbine control shall be transferred to the initial pressure regulator.
(k) The control rods shall be adjusted to provide the desired power distribution within the core.
l 7.3.3 Hot Start-Up Whenever the plant has been shut down for a period of time with the reactor vessel and auxiliaries remaining pressurized, a hot start-up procedure shall be followed to return the plant to service. This I
procedure will be essentially independent of the cause of shutdown assuming that the cause is recognized and any nonstandard conditions have been corrected. The reactor instrumentation shall be reset and downscaled and a hot start-up checklist shall be completed prior to the withdrawal of control rods.
A coupling integrity check shall be made in accordance with Section 5.2.2(d).
The start-up shall then proceed in accordance with Paragraphs (d) through (k) of Section 7.3.2 of the normal cold start-up procedure outlined above.
Proposed TSB0786-0125-NLO4
)
73 7.3.4 Normal Power Operation During normal power operation, the initial pressure regulator shall
]
maintain the reactor pressure at its rated value by operating the turbine admission valves. The turbine-generator load shall be established by the control rod positions. The principal function of the operating personnel during this period shall be as follows:
(a) The maintenance of a continuous watch in the control room for prompt attention to any annunciated alarms.
(b) The adjustment of the control rod pattern to accommodate changes in reactivity and to maintain the desired power distribution.
0 (c) The evaluation of abnormal conditions and the initiation of corrective action as required.
7.3.5 Extended Shutdown An extended shutdown shall be accomplished as follows:
(a) Reactor power shall be reduced by manipulation of the control rods, and the main generator load shall be decreased simultaneously. The turbine-generator shall be separated from the system.
(b) All control rods shall be inserted.
(c) The removal of reactor decay heat and the reduction of reactor pressure shall be accomplished by controlling reactor steam flow. The rate of cooling of the reactor vessel shall not be allowed to exceed 100*F per hour.
(d) The reactor shutdown cooling system shall be placed in operation whenever reactor pressure drops below a pressure sufficient to maintain turbine seals. This system will complete the cooling of the reactor water to 125'F.
(e) A minimum of one source range monitor channel and one power range channel shall be left in operation. All instrumentation pertaining to control of activity release shall be left in operation.
7.3.6 Short Duration Shutdown A shutdown of short duration may be accomplished while maintaining system pressure. The turbine-generator shall be unloaded and separated from the system. Reactor heat shall be accommodated by system losses or bypassing steam to the main condenser.
t Proposed TSB0786-0125-NLO4
74 7.4 REFUELING OPERATION The refueling operation shall be conducted in accordance with the following basic principles:
(a) Detailed written procedures shall be available prior to each refueling outage.
(b) The insertion and removal of fuel bundles and channels shall be done through the top of the reactor vessel after opening reactor vessel head closures as appropriate. Water shielding shall be provided by flooding the reactor vessel and the refueling extension tank. Fuel bundles and channels shall be handled by means of a grapple, transfer cask, and crane.
Fuel shall be replaced according to the following sequence:
(i)
Removal of selected bundles from core and transfer to spent fuel storage.
(ii)
Reshuffling of remaining bundles in core as desired.
(iii)
Insertion of new bundles in vacant positions as desired.
Shutdown margin verifications and suberiticality checks shall be made as required by Section 5.2.5.
Assembly replacement shall proceed as described above until the desired number of fuel assemblies have been changed.
(c) The trip devices specified in Section 6.3.1 shall be in service and connected to the reactor safety system during all refueling operations.
No additional instrumentation need be placed within the core lattice if the out-of-core instrumentation produces a significant response to the subcriticality check in the region to be altered. If this criterion cannot be met, a low-level neutron detector, measuring neutron flux, shall be located near the region to be altered.
In addition, both source range monitor channels shall be in i
service and measuring neutron flux during all REFUELING l
OPERATIONS.
(d) The procedure which shall be used for core alterations which increase reactivity shall be as outlined in Section 5.2.5(a).
Communications between the control room and the loading area shall exist during all core alterations.
l Proposed TSB0786-0125-NLO4
ATTACHMENT 2 Consumers Power Company Big Rock Point Plant Docket 50-155 SOURCE RANGE MONITOR (SRM)
SYSTEM DESCRIPTION August 15, 1986 i
I n
l l
i l
i 3 Pages l
i MIO786-0122-NLO4 i
.__..,.-__..m.__
SOURCE RANGE MONITOR (SRM) SYSTEM DESCRIPTION Source Range Monitor Channel 6 and 7 provide indication of neutron flux from
-3 source level to about 10 g og g,71 p,,,,,
Proportional counters RE-RG06A and RE-RG06B are boron-lined, argon-filled aluminum cylinders which detect neutron events and generate voltage pulses proportional to the magnitude of the ionizing event. These detectors are located in vertical tubes near the reactor vessel wall and can be positioned vertically by remote-manual controllers ICD-RF01A and ICD-RF01B on the control console. For a low-level start-up, the detectors must be positioned to their most sensitive, or "IN," position to detect a specified minimum count rate on the channel output indicators. These detectors can be moved to "MID" position to obtain two more decades of counting range on the indicators as the count rate output approaches full-scale. The detectors can'be moved to an "OUT" position when their useful monitoring range has been exceeded. This procedure extends the life of the detectors.
Triaxial cables are used to supply high voltage to the detector and to transmit the signal to current pulse amplifiers RT-RG03A and RT-RG03B (located in the outside cable penetration room). The current pulse amplifiers serve to amplify the pulses for source range monitors RT-RG07A and RT-RG07B. These amplifiers are transistorized units and have no controls. One cable connects the amplifier to the detector for the signal. Three cables connect it to the instrument: one for signal, one for high voltage, and one for low voltage to power the current pulse amplifier.
l The source range monitors are designed to measure source range neutron flux.
6 I
It covers a range of 0.1 to 1.0 x 10 counts per second.
I M70786-0122-NLO4
2 The instrument is constructed of standard plug-in modules in a chassis designed for instrument rack mounting. Maintenance is accomplished by module replacement. Chassis slides provide maintenance access to the top-loaded printed circuit cards when the instrument is in its extended position.
Instrument interfacing connectors are connected on the top rear section of the chassis deck.
Input signals, generated by the proportional counter through the current pulse amplifier, are conditioned and counted by a discriminator module which is tied to an internal computer bus. Discriminator adjustments are accomplished via the instrument's front panel interface. The logarithmic count rate function, the period measurement function, internal compensations, instrument calibration, and the alarm trip functions are performed by a microprocessor.
Outputs are via signal conditioning modules.
Alarm trip set points are stored digitally in nonvolatile microprocessor memory. An internal calibration check facility, automatic on-line calibration, instrument self-test, and operator / user prompting via the front panel display are provided.
The instrument contains a polarizing power supply for detector excitation.
Its output is adjustable under microprocessor control via the front interface panel. Detector power supply gross faiJure is annunciated and overvoltage protection is provided. The operator / user interface to the instrument is accomplished by an interactive control and display on the instrument front interface panel. Maintenance and operation includes setting alarm trip set points and polarization voltage, initiation of self-checks and calibration, and interrogation of the self-test system.
The primary function of the self-test system is to maximize instrument availability. The self-test capability assures that a module failure within the instrument is detected and annunciated within each thirty minute interval.
An alarm is actuated when the self-test system identifies a problem.
MIO786-0122-NLO4
__ ~ _ _.. _. _ _ _.
3 Three analog outputs are used: log count rate external meter and recorder and period external meter. The voltage level outputs drive remote log count rate meters RM-RG01A and RM-RG01B. The output voltage signals also drive one pen of two-pen continuous recorders RR-RH06A and RR-RH06B for. recording log count 6
rate. All indications range from 0.1 to 1.0 x 10 counts per second. The remote indicators are located on the control console and the recorders are located on the main control panel (CO2-1).
Output signals also drive remote period meters RM-RG02A and RM-RG02B located on the control console. These indicators range from -100 seconds to infinity to +10 seconds. A short period of +20 seconds initiates an alarm on the main control panel (CO2-1).
The source range monitors are not connected to the reactor protection system since the highest power level monitored is far below potentially hazardous power levels. These instrueents receive 120 Vac from reactor protection bus 1 and 2 through breakers CB30A1 and CB30A2.
M10786-0122-NLO4
.. e :
ATTACHMENT 3 Consumers Power Company Big Rock Point Plant Docket 50-155 SOURCE RANGE MONITOR BLOCK DIAGRAM (CHANNELS 6 AND 7)
August 15, 1986 i
l r
4 4
i I
i l
l 1 Page 1
I l
MIO786-0122-NLO4 L
c-o o e.
SOURCE RANGE MONITOR BLOCK DIAGRAM (CHANNEL 6 AND 7)
PROPORTIONAL COUNTER (RE-RG06A/B)
Ik 120 VAC V
SIGN AL J2 J1. l CURRENT p
PULSE JO J2A J4 AMPLIFIER (RT-RG03A/B)
SOURCE p
l J4 J5 RANGE ALARM l
[
HIGH MONITOR
(+ 20 m )
3 VOLTAGE (RT-RG07A/B)
-15 VDC l
J3 E
LOG PERIOD l LOG C i
i COUNT REC RDER (RM-RG01 A/B) (RM-RG02A/B)
(RR-RH06A/B)
(0.1 to 1.0X10' cps) (-100 to +10 sec) l l
.