ML17278B167
| ML17278B167 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 01/06/1987 |
| From: | WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | |
| Shared Package | |
| ML17278B166 | List: |
| References | |
| TAC-64358, NUDOCS 8701140450 | |
| Download: ML17278B167 (8) | |
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GONTROLLEB CQPY REACTIVITY CONTROL SYSTEMS BASES CONTROL RODS PROGRAM CONTROLS (Continued)
The RBM is designed to automatically prevent fuel damage in the event of erroneous rod withdrawal from locations of high power density during high power operation.
Two channels are provided.
Tripping one of the channels will block erroneous rod withdrawal soon enough to prevent fuel damage.
This system backs up the written sequence used by the operator for withdrawal of control rods.
3/4. 1.5 STANDBY LI UID CONTROL SYSTEM Insert From Attach A
The standby liquid control system provides a backup capability for bringing the reactor from full power to a cold, Xenon-free shutdown assumin that none of the withdrawn control rods can be inserted.
T meet this jective is necessary o ingec quantity boron w
ch pro u
s a concen ation of 660 ppm in he reacto core in roximate 90 to 1 minutes.
minimum quantity of 587 gall s of solu
'on contai ng a min um of 5500 ounds of sodium pe aborate 'equired o meet th'hutdown requiremen There is an additio 1 allow ce of 150 p
in the eactor cor to accoun for imperf ct mixiy.
The t e requireme was se cted to ov ride the activity i ertion r 4 due to ooldown foll in the eno ed inimum um in r e is 41.2 The minimum storage volume of the solution is estab-lished to allow for the portion below the pump suction that cannot be inserted and the filling of other piping systems connected to the reactor vessel.
The temperature requirement on the sodium pentaborate solution'is necessary to ensure that the sodium pentaborate remains in solution.
+uPO With ~uffdant. pumps and explosive injection valves and with a highly reliable control rod scram system, operation of the reactor is permitted to continue for short periods of time with the system inoperable or for longer periods of time with one of the redundant components inoperable.
Surveillance requirements are established on a frequency that assures a'igh reliability of the system.
Once the solution is established, boron concentration w'ill not vary unless more boron or water is added, thus a check on the temperature and volume once each 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> assures that the solution is available for use.
Replacement of the explosive charges in the valves at regular intervals will assure that these valves will not fai 1 because of deterioration of the charges.
B 3/4 1-4 Amendment No. 28 F
For Anticipated Transient Without Scram (ATWS), mitigatio'n requires an equivalent 86 gpm--
13% sodium nentaborate decahydrate pumping rate.
This requirement is met by running both standby liquid control (SLC) pumns simultaneously.
At the minimum allowable single numn pumping rate (41.2 gnm),
and with two pumps onerating, a 13.61 sodium nentaborate decahydrate concentrati on will nrovide the required equivalent injection rate.
Maintenance of the SLC solution volume and concentration within the limits established assure that the single pumn shutdown and ATWS requirements can be met.
87011+0450 87010b PDR ADOCK 05000397 P
PDR WASHINGTON NUCLEAR - UNIT 2
Attachment A - Insert to BASES 3/4. 1.5 To meet this objective, it is necessary to inject a quantity of boron whi ch produces a concentration of 660 ppm in the reactor core.
To account for imperfect mixing and leakage, an additional margin of 165 ppm boron equivalent is added.
For RHR shutdown dilution, an additional quantity of boron equivalent of and 275 ppm is added to assure the final concentration will not be less than 660 ppm in the reactor core.
To achieve this shutdown requirement, a minimum solution of 4587 gallons containing a minimum of 5500 pounds of sodium pentaborate decahydrate is required.
This quantity of sodium pentaborate decahydrate will provide an undiluted concentration of 1100 ppm of boron in the reactor core.
A minimum 41.2 gpm per pump injection rate has been selected to override the reactivity insertion rate due to cool down and zenon decay.
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~C 60 CO '
40 ON 20 LCNOkla COtiC&CTRATX)N UMK ACXFTASLE TEQttRATVltK REGCIH SOLlJTlON CONCKNTRATlON (% BY %EIGHT)
SOOIUM PMTABORATE SOLUTION SATURATIONTcJHP~TURE RGURE 3.1.5-1 WASHlNGTON NUC~R UNlT 2 3/4 1-21
X g
hh I=
Bf g
gg 12 13.B 13.4 12.0 MNIIMUM:
VOLUME.
LIIIE APPROVED VDLUM M
lgUM COOCEIITR TIO LNE RC AT RECOMMENDED
'TANKLEVELMARGN
~ OF d NcllES BELOW OVERFLOW OVERFLOW VOLUME LNE 4500 4SBV 4500 1700 4920 4800 4900 NET TANKVOLUME(OALIONS) 500 6100 6150 5200 SODIUM PENTABOBATETANK,VOLUMEVS. CONCENTRATION BEQUIAEME 8
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FIGURE 3.1.5-2
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(0 g 15 I'C CD CO HZ I
CL 12 LOYl LEYEL ALARM 4587 HIGH LEYEL ALARM 4950 nacho@ or sos nomen
- ~ VOLUND Co)ICEHTAA2IOH Lg OYERFLOYf YOLUME 5150 4500 4600 4700 4800 4900 5000 S100 5200 5300 NET TANK YOLUME (GALLONS)
SODIUM PENTABORAl E TANK, VOLUME VS. CONCENTRATION REQUIREMENTS
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