ML20094F424

Proposed TS 3/4.1.3 Re Movable Control Assemblies

ML20094F424
Person / Time
Site:	Davis Besse
Issue date:	02/12/1992
From:	CENTERIOR ENERGY
To:
Shared Package
ML20094F420	List: ML20094F419 ML20094F424
References
NUDOCS 9202240264
Download: ML20094F424 (2)

Text

Docket Number 50-346

- License Number NPF-3

, cerial Number 2020 I . Attachment 1 lPage 1

REACTIVITY CONTROL SYSTEMS I

il

(( BASES i'

i

!i3/4.1.3.

MOVABLE CONTROL ASSEMBLIES (Continued)

The maximum rod drop time pennitted is consistent with the assumed rod drop I time used in the safety analyses. Measurement with T > 525'F and with

~

i!reactorcoolantpumpsoperatingensuresthatthemeasNddroptimeswillbe il representative of insertion times experienced during a reactor trip at

((operatingconditions.

. 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 frequent

., verifications required if an automatic monitoring channel is inoperable.

!! These verification frequencies are adequate for assuring that the applicable

<lLCO's are satisfied. A 1.5% group average position uncertainty is applied to ll the rod index curves. Therefore, the position indicators must be capable of j ! supporting this accuracj. The Surveillance Requirement ensures this accuracy

>! by keeping the RPI calibrated to a "known" position as indicated by the API.

Il Using the API as a "known" position is valid provided two consecutive reed

{!switenesarenotinoperable. Having one entire string (i.e. , every other reed 4 { switch) inoperable is acceptable.

!! specific surveillance of the reed switches is not required because:

,,A i,

j ' 1) When one or more reed switch fails closed, a large API indication of

asymmetry occurs.

l; 2) T$ o failed open reed switches in series result in a large indication

.- of asymetry.

ll 3) Failed open reed switches not in series (up to every other switch) are bounded by tne analysis, ie ilTherefore, a reed switch condition not bounded by the analysis will be I indicated by API system asymetry indications, j

3.1.3.6 (Regh%3 Technical Specification 3.1.3.8 provides the ability to prevent excess 1,e i

power peaking by transient xenon at RATED THERMAL POWER. Operating restric-tions resulting from transient xenon power peaking, including xenon-free y startuo, are inherently included in the limits of Sections 3.1.2 Rod Insertion Limits), 3.1.3.9 (Axial Power Shaping Rod Insertion Limits), and 3.2.1 ( Axial Power Imbalance) for transient peaking behavior bounded by the following factors. For the period of cycle operation where regulating rod groups 6 and 7 are allowed to be inserted at RATED THERMAL POWER, an 8% peaking increase is applied at or above 92% FP. An 18% increase is applied below 92",

FP. For operation where only regulating rod group 7 is allowed to be inserted at RATED THERMAL POWER, a 5% peaking increase is applied at or above 92% FP l

and a 13". increase is applied below 92% FP.

DAVIS-BESSE, UNIT 1 B 3/4 1-4 Amendment No. 45,162 1

9202240264 920212 6 ADOCK 0500 gDR

Docket Number 50-346

' Libense Number NPF-3 bNrial Number 2020 A tat a c hme n t 2

.Page 1 REACTIVITY CONTROL SYSTEMS BASES 3/4.1.3. MOVABLE CONTROL Ab'EMBLTr5 (Continued) a The maximun rod drop timeJperuitted is consistent with the assumed rod drop time used in the saf ety analyses. Measurement with 5T yg 2 525'T and with re-actor coolant pumps operating ensures that the measured drop times vill be representative of insertion times experienced during a teactor trip at operat-ing conditions. .

Control rod positions and OPERABILITY of the rod position indicators are re-quired 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 frequent verifications required if an automatic monitoring channel is inoperable. These verification frequencies are adequate for assuring that the applicable LCO's are satisfied.

Technical Specification 3.1.3.8 provides the ability to prevent excessive power peaking by transient xenon at RATED THERMAL POWER. Operating restric-tions resulting frem transient xenon power peaking including xenon-f ree is #"

startup, are inherently included in the limits of Sections 3.1.3.6 (Regulat-ing Rod Insertion Limits) . 3.1.3.9 (Axial Power Shaping Rod Insertion Limits),

and 3.2.1 ( Axial Power 1mbalance) for transient peaking behavior bounded by the folleving factors. For the period of cycle operation where regu) sting rod groups 6 and 7 are allowed to be inserted at MTED THERMAL POWER, an 8%

peaking increase is applied at or above 92% TP. An 18% increase is applied belov 92% TP. For operation where only regulating rod group 7 is allowed to be inserted at RATED THERMAL P0k'ER, a 5 peaking increase is applied at or above 92% TP and a 13% increase is applied belov 92% TP. g i

If these values, checked every cycle, conservatively bound the peaking ef f ects of all transient xen6n, then the need for any hold at a power level cutoff be-lov RATED THEPEAL P0kTR is precluded. If not, either the power level at which the requirements of Section 3.1.3.8 must be satisfied or the above-listed f ac-tor's vill be suitably adjusted to preserve the LOCA linear heat rate limits.

The 11 citation on axial 'pover ' shaping red insertion is necessary to ensure that+pover peaking limits r e not exceeded.

t

? DAVIS-EESSE, UNIT 1 B 3/4 1-4 Amendment No. 2&,45 9

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