ML20214P619
| ML20214P619 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/22/1987 |
| From: | NORTHEAST NUCLEAR ENERGY CO. |
| To: | |
| Shared Package | |
| ML20214P617 | List: |
| References | |
| NUDOCS 8706030463 | |
| Download: ML20214P619 (8) | |
Text
Docket No. 50-245 B12530 Millstone Nuclear Power Station, Unit No.1 Proposed llevision to Technical Specifications Standby Liquid Control System May 1987 0706030463 970522 PDR ADOCK 05000245 Y
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b LIMITING CONDITION FOR OPERATION i
i 34 STANDBY LIQUID CONTROL SYSTEM l
Applicability:
i Applies to the operating status of the standby liquid control system.
Objective:
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To assure the availability of the standby liquid control system.
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Specifications l
A.
Normal Operation
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During periods when fuel is in the reactor, the liquid poison system shall l
j be operable, except when the reactor is in the Cold Shutdown Condition and all control rods are fully inserted and Spooitication 3 3.A is mot, except as noted in Specification 3.4.B below.
1 SURVEILLANCE RRQUIREMENT I
4.4 STANDBY LIQUID CONTROL SYSTEM Applienbiitty:
1 i
Applies to the periodio testing requirements for the standby liquid control t
i system.
Objootivo To verify the operability of the standby liquid control system.
i 1
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Spnotrications i
A.
Normal Operation i
i The operability of the standby liquid control system shall be verified by i
i performance of the following tests:
1 1.
At leant onco per month Domineralized water shall be recycled to the test tank. Pump minimum flow rate of 40 gpm shall be verified against a system hond l
corresponding to a renotor vossol pressure of 1225 pais.
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l H111 stone Unit 1 3/4 4-1 l
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LIMITING CONDITION FOR OPERATION 34 STANDBY LIQUID CONTROL SYSTEM C.
Boron Requirements The liquid poison tank shall contain a boron-bearing solution that natisfies the following requirements at all timos when the liquid poison system is required to be OPERABLE:
o Doron enrichment (atom % B-10) 2:50%, and o
Solution concentration till wt%, and i
o Solution volumo 21,850 gallona, and o
The temperature of the solution, including that in the piping, shall not bo less than the temperature presented in Figuro 3.4.1.
t D.
Shutdown Requirement If Spoolrications 3 3.A through C are not mot, an orderly shutdown shall be initiated.
SURVEILLANCE REQUIREMENT 4.4 STANDBY LIQUID CONTROL SYSTEM C.
The availability of the proper boron-bearing solution shall be verified by performance of the following tests.
1.
At loant onco por month Doron conoontration shall be datormined.
In addition, the boron concentration shall be datormined any timo water or boron is added or if the solution temperaturo drops below the limits apoeiriod by Figuro 3 4.1.
2.
At lonst onon por day Solution volumo shall be checked.
3.
At lennt once por day The colution temperature, including that in the piping, shall be chooked.
4.
At lonnt onoo por rnfunling cyclo Doron-10 onrichmont shall bo datormined.
In addition, tho boron-10 onrichmont shall bo datormined within 60 days of adding nodium pontaborato to the tank.
Millatone Unit 1 3/4 4-4
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l 34 STANDBY LIQUID CONTROL SYSTEM DASES l
A.
Normal Operation The design objootivo of the liquid control system is two fold. One objectivo is to provide the capability of bringing the reactor from full power to a cold, xenon-free shutdown assuming that none of the withdrawn control rods can be inserted. To moet this objective, the liquid control system is designed to injoot a sufficient quantity of Boron-10 (the boron isotope with the higher neutron absorption cross-section) in less than 125 minutos to bring the reactor from full power to a minimum of 2.6% delta K suboritical condition considering the hot to cold reactivity swing, xenon poisoning, analytical biases and uncertainties, etc. This quantity is equivalent to the quantity of naturally occurring boron which produces a concentration of 660 ppm.
An additional 25% of boron solution is provided for possible imporrect mixing of the chemical solution in the roaotor coolant. A minimum quantity of 1,610 not gallons of 50% B-10 onriched sodium pontaborate in a solution having a concentration of no loss than 10 wt% (the higher minimum solution concentration in the LCO accounts for the measurement uncertainty) is required to moot this shutdown requirement.
Actual minimum system volume for this quantity is 1,850 gallons.
(240 gallons are contained below the pump suction and, therefore, cannot be inserted.)
The timo requirement (125 minutos) for insortion of the boron solution was 1
selected to overrido the rate of reactivity insertion due to cooldown of the reactor following the xenon poison peak.
l The second objootivo of the liquid control system is to moet the requirement of the ATWS rule (10CFR50.62) which states that, in part:
"Each boiling water reactor must have a standby liquid control system (SLCS) with a minimum flow capacity and boron content equivalent in control capacity to 86 gallons por minuto of 13-weight percent sodium l
pentaborate solution."
The equivaloney requirement is mot by satisfying the following equations:
i E6, M251, C_,
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31 M
13 19.8 Whore I
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Flowrate from one SLCS pump, 38 gpm.
(The higher value specified in the LCO accounts for the measurement uncertainty).
Millstone Unit 1 B 3/4 4-1 i
34 STANDBY LIQUID CONTROL SYSTEM (con't.)
DASES M251 :
The ratio of mass of water in the reactor vessel and M
reoirculation system at hot rated conditions for a plant with a vessel diameter of 251 inches to that of Millstone Unit 1.
(This ratio is greator than 1.25).
C Sodium pentaborate solution conoontration, 10 wt$ (the higher value specified in the LCO accounts for the measurement uncertainty).
E B-10 isotopo enrichment, 50 atom porcent.
Doron conoontration, solution temperature (within the tank and connecting piping including chock of tank heater and pipe heat tracing nyatem), and volumo are checked on a frequency to assure a high reliability of operation of the system should it ever be required. Experience with pump operability indicates that monthly testing is adequato to detoot if failures have occurred. Testing of D-10 enrichment once per refueling cycle or whenever nodium pontaborate is added to the tank providos sufficient assurance that the minimum B-10 enrichment will be maintained.
Components of the system are checked periodica11y, as described above, and make a functional test of the entire system on a frequency of less than l
onco during each operating cycle unnecessary. A test of one installed explosive charge is mado at least onco during each operating cycle to assure that the chargos are natisfactory. The replacement charge will bo solooted from the same batch as the testod chargo.
A continual check of the firing circuit continuity is provided by pilot lights in the control room.
The relier valves in the standby liquid control ayatem protect the ayatem piping and positivo displacement pumps, which are nominally designed for 1500 psi, from overprosaure. The prosauro ro11of valvos discharge back to the standby liquid control solution tank.
Millstone Unit 1 D 3/4 4-ta
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l 34 STANDBY LIQUID CONTROL SYSTEM BASRS I
B.
Operation with Inoperablo Components Only one of the two standby liquid control pumping circuita is needed for i
propor operation of the ayatem.
If one pumping circuit la found to be inoperable, there is no immediate threat to shutdown capability, and reactor operation may continue while repatra are being made.
l C.
Horon Requirements The solution naturation temperature of 13% sodium pontaborate, by weight, i
is 580F. The solution shall be kept at least 100F above the naturation temperature within the tank and auction piping to guard against boron l
proolpitation. The 100F margin la included in Figure 3.4.1.
Temperatura l
l and liquid level alarms for the ayatem are annunciated in the control
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room.
Pump operability la checked on a frequency to assure a high reliability of operation of the ayatom should it over be required.
J Once the solution has boon mado up, boron concentration will not vary untosa more boron or more wator is added or removed. Lovel indication and i
alarm indicate whether the solution volumo has changed which might indicato a possible solution conoontration change. Considering those factors, the toat interval has boon estat11ahed.
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Milletone Unit 1 B 3/4 4 2
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