ML20247A696
| ML20247A696 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 03/21/1989 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML20247A700 | List: |
| References | |
| NUDOCS 8903290170 | |
| Download: ML20247A696 (2) | |
Text
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4 s., ",.,-
REACTIVITY CONTROL SYSTEMS
-BASES
$0RATIONSYSTEMS(Continued)
With the RCS temperature below 200*F, one Boration System is acceptable without single failure consideration on the basis of the stable reactivity condition of the reactor and the additional restrictions prohibiting CORE ALTERATIONS and positive reactivity changes in the event the single Boron InjectionSystembecomesinoperable.
The limitation for a maximum of one centrifugal charging pump to be OPERABLE and the Surveillance Requirement to verify all charging peps except the required OPERABLE pump to be inoperable in MODES 4, 5, and 6 provides assurance that a mass addition pressure transient can be relieved by the opera-tion of a single PORY or an RNR suction relief valve.
The boron capability required below 200*F is sufficient to provide a.
SHUTDOWN MARGIN of 1% Ak/k after xenon decay and cooldown from 200'F to 140*F.
This condition requires either.2968 gallons of 7000 ppe borated water from the boric acid storage tanks or.14,071 gallons of 2400 ppe borated l
water free the RWST.
The contained water volume limits include allowance for water not available because of discharge line location and other physical characteristics. In the case of the boric acid tanks, all of the contained volume is considered usuable.
The required usable volume may be contained in either or both of the.
boric acid tanks.
The limits on contained water volume and boron concentration of the RWST also ensure a pH value of between 8.5 and 11.0 for the solution recirculated within containment after a LOCA.
This pH band minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components.
The OPERABILITY of one Boration Systes during REFUELING ensures that this system is available for reactivity control while in MDDE 6.
3/4.1.3 MOVABLE CONTROL ASSEMBLIES' The specifications of this section ensure that: (1) acceptable power distribution limits are maintained, (2) the minimum SHUTOOWN MARGIN is main-N tained, and (3) the potential effects of rod misalignment on associated acci-J8 dent analyses are limited.-
OPERABILITY of tho' control rod position indicators N80-is required to. determine control rod positions and thereby ensure compliance with the control rod ali,gnment and insertion limits.
oo Verification that the Digital Rod Position Indicator agrees with the demanded position within i 12 steps at 24, 48, 120, and 228 steps withdrawn for the Control Banks and 18,
.g 210 and 228 steps withdrawn for the Shutdown Banks provides assurances that'the so 58 Digital Rod Position Indicator is operating correctly over the full range of indication.
our Since the Digital Rod Position System does not indicate the actual N
shutdown rod position between 18 steps and 210 steps, only points in the gg indicated ranges are picked for verification of~ agreement with demanded position.
coa.a.
WOLF CREEK - UNIT 1 8 3/4 1-3 Amendment No. 23 '
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REACTIVITY CONTROL SYSTEMS BASES
'l MOVABLE CONTROL ASSEMBLIES (Continued)-
For nrposes of determining compliance with Specification 3.1.3.1, any immovability of a control rod inv0kes ACTION Statement 3.1.3.1.a.
Before utilizing ACTION Statement'3.1.3.1.:, the rod control urgent failure alarm must be illuminated:or an electrical problem must be detected in the rod control system.. The rod is considered trippable if the rod was demonstrated OPERABLE during the last performance of Surveillance. Requirement 4.1.3.1.2 and met the rod drop time criteria of Specification 3.1.3.4 during the last performance of Surveillance Requirement 4.1.3.4.
The ACTION-statements which permit limited variations from the basic requirements are accompanied by additional restrictions which ensure that the
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- original design criteria are met. Misalignment of a rod requires measurement of peaking factors and a restriction in THERMAL POWER. These restrictions-revide assurance of fuel rod integrity during continued operation. In addition, those safety analyses affected by a misaligned rod are reevaluated to. confirm that the results remain valid during future operation.
The maximum rod drop time restriction is consistent with the assumed rod drop time used in the safety analyses. Measurement with T,yg greater than or equal to 551*F and with all reactor coolant pumps operating ensures that the measured drop times will be representative of insertion times experienced during a Reactor trip at operating conditions.
Control rod positions and OPERABILITY of the rod position indicators are.
required to be verified on a nominal basis of once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> with more' frequent verifications required if an automatic monitoring channel 'is. inoperable.
These verification frequencies are adequate for assuring that the applicable -
tCOs are satisfied.
WOLF CREEK - UNIT.1 B 3/4 1-4 Amendment.No. 27.
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