ML20106D782

Application for Amends to Licenses DPR-24 & DPR-27, Clarifying Definition of Fully Withdrawn as Concerns Rod Cluster Control Assmeblies,Per Table 15.3.5-5,Section 15.3.10 Re Control Rod & Power Distribution Limits

ML20106D782
Person / Time
Site:	Point Beach
Issue date:	10/06/1992
From:	Link B WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20106D787	List: ML20106D782 ML20106D789
References
CON-NRC-92-114 VPNPD-92-321, NUDOCS 9210140301
Download: ML20106D782 (8)

Text

w . . . - , . . -- - ._ -- -

g,,

.. k $ i[ - 6 s

s.  ;

Wisconsin C "

1 Electnc

.-POWER COMPAN\ .

23' W Mcher.PO Box 2046 .mAee # 53201 (414122i2345 VPNPD-925321' 10 CFR-50.4 j NRC-92-114 10 CFR 50.90 J '

0..cobur 6,.1992 a-ument Control Desk

. 2 5. NUCLEAR PEGULATORY COMMISSION wail Station P1-137- _,

'shington, DC 20555 C,tntlemen:

DOCKETS 50-266 AND 50-3Q1 IECliNICAL SPECIFICATIONS CHANGE REOUEST 151 DOCOMENTATION OF ROD *'9ITION Ib STEPS VICE INCI1ES POINT BEACH NUCLEAE_J " d NITS 1 AND,R In accordance with the requitoments oi '3 R 5 0. 4 and 50.90,  : i Wi Acc,nsi 4 '?'nctric Powcr Company (Licaw a) hereby requests-amendm 4 *0 Facility Operating Licenses DPR-24 and DPR-27 for .,.;

~ oint Bc. '

Nuclear Plant,~ Units 1 and 2 respectives2y,_to acorporate changns to the Plant-Technical Specifications. The ,

proposed ravision changes all references of rod-position in.the TechnicL3: Specifications to units of _ steps rather than inches.

A revision to the basis for Section:15.3.10, " Control-Rod and Potter.

Distribution. Limits," is also proposed to clarify the oefinition of

-" fully withdrawn" as=it concern 6 Rod' Cluster Control Assemblies.

Revisions to Table 15.3.5-5,--Section 15.3.10, the basis _for Section'15.3.10, and Figure 15,3.10-l'are proposed to-support this' change. Marked-up Technical; Specification pages, a_ safety ,

evaluation, and the r.o significant1 hazards __ consideration are-d enclosed.

i DESCRIPTION OF CURRENT LICENSE CONDITION l

.- Currently, in Section-15.3.10, " Control Rod and Power.DistriMtion D Limits," and Table 15.3.5-5, " Instrument Oportting Conditions for, l Indications,"-of the PBNP Technical Specifications, red position L is referenced in both units of steps and inches. Additionally, L

- P i g u r e .1 5 . 3 . 1 0 " 1 ,- " Control' Bank, Insertion Limiss Point Beach Units 1 and 2," references rod position in percent vithdrawn.

I l

K. 9g10140301 921006o 2J1 00, I .

p '.. r MCK<05000266:

PDR

- a g), a P: w.w,qgunwumamcmw

Document Control Desk October 6, 1992 Page 2 The control rod fully withdrawn position is. defined as a bank demand position equal to or greater than 225 steps. This definition is applicable to both shutdown and control banks.

References to the " fully withdrawn position are found in Section 15.3.10, " Control Rod and Power Distribution Limits."

?ESCRIPTION OF PROPOSED CHANGES This Tuchnical Specification Change Request proposes several related changes. The proposed changes are as follows:

1. Revise all references of rod position in Section 15.3.10 and Table 15.3.5-5 from units of inches to ualts of p steps. These changes ensure that references to rod position are consistent throughout the PBNP Technical Specifications.

2. Revice Figure 15.3.10-1 to reference control bank o pos!. tion in units of steps instead of the currently used unit of percent withdrawn.

3. In order to clarify the definition of " fully withdrawn,"

the second paragraph of the Basis for Section 15.3.10 is being revised to read:

"During power operation, the shutdown banks are fully withdrawn. Fully withdrawn is defined as a bank demand -

position equal to or greater than 225 steps. Evaluation -

has shown that positioning control rods at 225 steps, or greater, has a negligible effect on core power distti-butions and peaking factors. Due to the low react.vity worth in this region of the core and the fact that, at 225 stcps, control rods are only inserted one step into the active fuel region of the core, positioning rods at this position or higher has minimal effect. This posi-tion is varied, based on a predeterminad schedule, in order to minimize wear of the guide cards in the guide tubes of the RCCAs "

4. Item 2 of Section 15.3.10.A on page 15.3.10-1 is revised to reference Footnote (1). This is proposed because the footnote is applicable to both shutdown and control banks. Item 2 of Section 15.3.10 A di cusses control bank position.

l l

Document Control Desk October 6,-1992 Page 3 S. P.evise Figure 15.3.10 by adding the following explanatory note:

"The ' fully withdrawn' parking position range can be used witho t violating is Figure."

BASIS AND JUSTIFICATION Section 15.3.10, " Control Rod and Power Distribution Limits,"

ensures core subcriticality following a reactor trip, a limit on potential reactivity in*ortions from a hypothetical rod cluster control assembly ejection, and an acceptable core power distri-

~

bution during power operation. The changes to this section will reference rod position in units of steps to ensure consistency throughout this section. These changes additionally will reference rod position so that it corresponds with the control room indications used by the operators.

Table 15.3.5-5, " Instrument Operating Conditions for-Indications,"

specifies the number of available' channels and the minimum number of operabl~ channels required for various functional indicators.

This table also specifies the operator astion required if the-minimum conditions cannot be met. The proposed ra._, ion changes the reference to roj position in the operator action column cf the

" Control Rod Misafignment" portion of this tab'.e.

Figure 15.3.1L-1, " Control Bank Insertion Limits Point Beach Units 1 and 2," specifies control bank insertion limits that must be maintained to ' ensure tlua ability to achieve hot shutdown following a reactor trip anytime during core life. These~ limits assume that the control rod with the highest reactivity _ worth

-ramains fully withdrawn, and include a 10% margin in reactivity worth of the applicable control rods. These' limits also provide a limit on the maximum inserted rod worth in the event of a hypo-thetical rod ejection while still maintaining nuclear. peaking factors within acceptable limits.

These-proposed amendments change the reference-of control bank position on the figure from percent withdrawn to steps withdrawn.

This change will reference control bank position to correspond to the actual control room indications. Additionally, a note will be-add 2d to the bottom of the figure to indicate the " fully withdrawn"'

. parking position as it relates to control bank insertion limits.

In summary, all of these changes are being proposed in response to a request from the plant operators. These changes will update the PBNP Technical Specifications so th't rod position is referenced in i

t 4 Document Control Desk

' October 5, 1992-Page-4 the Technical Opecifications using the same units as indicated-in the control room. These changes.are not safety significant, but will enhance the ability of the operators to safely operate the plant. Please process this change-in a timely manner.-

Please contect us if there are any questions.

Sincere y, 4#

[la Q/

Bob Link s

Vice President -

Nuclear Power

-FDP/jg Enclosures cc: NRC Resident Inspector NRC Regional Administrator Public Service Commission of Wisconsin Subscribed and sworn before me on- #

this G riday of &ttG&c 4, 1992.-

dL(suals,h714%u.4et.-

Notary Public,'iState of Wisconsin l My Commission expiren ( F c. .

t I

i I

l-

__ _ ________-_s -

TECFNICAL SPECIFICATION CHANGE REOUEST 151 i SAFETY EVALUATION j INTRODUCTION: l Wisconsin Electric Power Company (Licensee) has applied for

~

amendments for Facility Operating Licenses DPR-24 and DPR-27 for l Point Beach Nuclear Plant, Units 1 and 2. These amendments l propose.to change all references of rod position in_the PBNP l Technical Specifications to units of steps. These proposed amendments additionally clarify the definition of " fully withdrawn" as it refers to Rcd Cluster Control Assemblies.

EVALUATION:

Presently, in Section 15.3.10, " Control Rod and Power Distribu- -

tion Limits" and Table 15.3.5-5, " Instrument Operating Conditions.

for Indications" of the Technical Specifications, rod position is referenced in both units of inches and steps. The unit of steps is the preferred reference because it corresponds to indications

-used by the operators at Point Beach Nuclear Plant.- One step equals 5/8 inch of rod. motion. Since there is a direct corre-lation between steps and inctes, this revision is simply a' change in format to ensure that the Technical Specifications are consis-tent with respect to rod position.

Figure 15.3.30-1, " Control Bank Insertion Limits Point Beach Units 1 and 2" references control bank position in percent with-drawn. In this figure, control bank position is based on 229 steps being equal to 100% withdrawn. Since there is a direct correlation between steps and the percent withdrawn position, this proposed revision is simply a change in format that will make the f3gure easier for the operators to use. Currently, the three inse? ; ion limits -

s for banks B, C, and D intersect the y-axis of the figure at 77, 22, and 81 percent withdrhwn, respectively. When' converting these three intercept paints to units of steps, the values will be rounded up, in the conserva- ,

tive direction, to the next whole step value. This will result in the three intercept points being listed in the figure as 176, SA, and 186 steps, respectively.

' Additionally, in order to clarify the definition of " fully withdrawn," the basis for Section 15.3.10 is being updated. The definition of " fully withdrawn" was most "ecently changed by Amendments 88 and 93 to Facility Operating Licenses DPR-24 and DPR-27.respectively. These amendments approved a change to the control rod fully withdrawn position from 228 steps to a bank

-demand position equal to or greater than 225 steps. This defi-nition is applicable to both shutdow?. and control banks. An evaluation performed by Westinghouse in 1984, allowed the 1

licensee to lower the fully withdrawn parking position of shut- 3 dr"in and_ control banks'from 228 steps to 225 steps. At 225 s eps, the rods are only 0.3 inches into the active fuel region, and_at:228-cteps, the rods are above the active fuel region.

Because of the low rerctivity worth in this region of the core, the evaluation concluded that the effects on power distribiltions and core peaking factors would be minimal, and that these new power distributions and core peaking factors were still.well within the required safety margins. This lower allowed parking position was implemented in order to minimize wear of the guide cards in the guide tubes of the Rod Cluster Control Assemblies.

Based upon a predetermined schedule, the parking position for different operating cycles will. vary from 225 steps to 223 steps.

This parking position is the same for both shutdown and control banks. Each core's reload safety evaluation will determine the adequacy of this parking position.

This definition of parking position could, however, cause some confusion during the use of Figure 15.3.10-1, "Contrnl Bank Insertion Limits Point Beach Units 1 and 2" during certain operating cycles. The amendments proposed by this Technical Specification change request propose to reference control bank posit'.on in steps. This figure is based on the 100% withdrawn position being equal to 228 steps. Therefore, during the operating conditions when the parking position 2s set below 228 steps, it would appear as if a violation of banks B and C would potentially exist. To prevent any confusion, a note is being added to this figure that will explain that a " fully withdrawnh L position range of 225 to 228 steps can be used without violating j this figure.

CONCLUSIONS:

In summary, changing the reference of rod position to units of steps instead of inches will make the Technical Specifications conuistent with respect to rod position. This change will also reference rod position in units that are identical to the operator's control room _ indications. Additionally, in order to clarify the definition of " fully withdrawn," an explanatory paragraph will_be added to the basis for Section 15.3.10 to describe the background and reasons for this defined position.

This update to the basis will not change the way that Point Beach l- Nuclear Plant is operated.

l 2

t

, ._. - _ , ~ _ _ . - . _ _ . _ ,

TECHNICAL SPECIFICATION CHANGE REOUEST 151 "NO SIGNIFICANT HAZARDS" CONSIDERATION l

l In accordance with the requirements of 10 CFR 50.91(a),-Wisconsin '

. Electric Power Company-(Licensee) has evaluated _the proposed changes against the standards of 10 CFR-50.92 and have determined that the operation of Point Beach Nuclear Power Plant Units l_and .i 2-in accordance with the proposed amendments does not present a -i significant hazards consideration. The analysis of t e require-ments of in CFR 50.92 and the basis for this conclusion is as follows:

1. Operation of this facility under the proposed Technical Specification-change will not create a significant increase in the probability or consequences of an accident previously evaluated. This proposed change simply revises all references of rod position in the Technical-Specifications, to units of steps. There is s direct correlation between steps, inches, and percent withdrawn. Therefore, this is only a format change, making all references to rod position consistent throughout the Technical Specifications and with control bo;rd indications. AdditionrJ1y, updating the basis of Section 15.3.10 is proposed to clarify the definition of " fully withdrawn" as it concerns Rod cluster Control Assemblies. This basis change will not change the way that the plant is operated because the parking position of the shutdown and control banks will still be based upon a predetermined-schedule that varies parking position, on a cycle-to-cycle basis, as appropriate, to minimize RCCA wear. Each core'sLreload safety evaluation is also used tc ensure that this parking pcsition is adequate. There is no physical change to the facility, its systems, or its operation.

Therefore, an increased probability or consequences of an accident previously evaluated cannot occur.

2. Operation of this facility under this proposed Technical Specification change will not create the possibility of a new or different kind of accident from any: accident previously evaluated. This proposed chang simply revises all references of rod position in the Tecnnical Specifications, to units of steps. There is a direct correlation between steps, inches, and i

percent. withdrawn. Therefore, this is only a format E change,. making all references to rod position consis-tent throughout the-Technical Specifications and with control board indications. Additionally, updating the basis of Secticn 15.3.10 is proposed to clarify the definition of " fully withdrawn" as it concerns Rod 1

l.

i

, ,-- - .- m

4 Cluster Control Assemblies. This basis change will not change.the way that the plant is~ operated because the parking position of-the shutdown and control banks will still be based upon a predetermined cchedule that varies parking position, on a cycle-to-cycle basis, as -

appropriate, to minimize RCCA wear. Each core's reload safety evaluation is also used to ensure that this parking ponition is adequate. There is no physical y change to ao facility, its systems, or its operation.

Therefore, a new or different kind-of accident cannot occur.

3. Operation of this facility under this proposed Technical Specification change will not create a significant reduction-in u margin of safety. This proposed change simply revises all references of rod position in thu Technical Specifica-tions, to units of steps. There is a direct correlation

, between steps, inches, and percent withdrawn. Therefore, l; this is only a format change, making all references to rod

! position consistent throughout the Technical Specifications and with control board indications. Additionally, updating the basis of Section 15.3.10 is proposed to clarify the definition of " fully withdrawn" as it concerns Rod Cluster-Control Assemblies. This basis change will not change-the way that the plant is operated because the parking position i of the shutdown and control banks wil] still be based upon-a-predetermined schedule that varies parking position, on a cycle-to-cycle basis, as appropriate, to minimize RCCA wear. '

l Each core's reload safety evaluation is also used to ensure

! that this parking position is adequate. There is no

! physical change to the facility, its systems, or its l operation. In fact, this change enhances the ability of the operators to safely operate the plant by presenting the operators with Technical Specification information for rod position in units consistent with existing plant instrumen-tation. A margin of safety may therefore increase. There-l fore, a significant reduction in a margin of safety cannot l occur.

o I

l l.

2 l

l