ML040620435

Technical Specification Bases Changes

ML040620435
Person / Time
Site:	Catawba
Issue date:	02/19/2004
From:	Jamil D Duke Energy Corp
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML040620435 (10)

Text

Duke UowPowere A Duke Energy Company D.M. JAMIL Vice President Duke Power Catawba Nuclear Station 4800 Concord Rd. / CNO IVP York, SC 29745-9635 803 831 4251 803 831 3221 fax February 19, 2004 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555-0001

Subject:

Duke Energy Corporation Catawba Nuclear Station, Units 1 and 2 Docket Nos. 50-413 and 50-414 Technical Specification Bases Changes Pursuant to 10CFR 50.4, please find attached changes to the Catawba Nuclear Station Technical Specification Bases.

These Bases changes were made according to the provisions of 10CFR 50.59.

Any questions regarding this information should be directed to L. J. Rudy, Regulatory Compliance, at (803) 831-3084.

I certify that I am a duly authorized officer of Duke Energy Corporation and that the information contained herein accurately represents changes made to the Technical Specification Bases since the previous submittal.

Dhiaa M. Jamil Attachment i4-VO oI www.duke-energy. corn

U.S. Nuclear Regulatory Commission February 19, 2004 Page 2 xc:

L. A. Reyes, Regional Administrator U.S. Nuclear Regulatory Commission, Region II S. E. Peters, Project Manager U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation, Mail Stop 0-8-G9 E. G. Guthrie Senior Resident Inspector Catawba Nuclear Station

Duke DUKE POWER wPO were Catawba Nuclear Station A Duke Energy Company 4800 Concord Rd.

York, SC 29745 803 831 3000 February 19, 2004 Re:

Catawba Nuclear Station Technical Specifications (TS) Manual Please replace the corresponding pages in your copy of the Catawba Technical Specifications Manual as follows:

REMOVE THESE PAGES INSERT THESE PAGES List of Effective Pages Page 14 Page 14 Tab 3.1.7 Bases B 3.1.7 B 3.1.7-6 B 3.1.7 B 3.1.7-6 If you have any questions concerning the contents of this Technical Specification update, contact Jill Ferguson at (803) 831-3938.

Lee A. Keller Manager, Regulatory Compliance www. duke-energy. corn

Page Number B 3.1.6-5 B 3.1.6-6 B 3.1.7-1 B 3.1.7-2 B 3.1.7-3 B 3.1.7-4 B 3.1.7-5 B 3.1.7-6 B 3.1.8-1 B 3.1.8-2 B 3.1.8-3 B 3.1.8-4 B 3.1.8-5 B 3.1.8-6 B 3.2.1-1 B 3.2.1-2 B 3.2.1-3 B 3.2.1-4 B 3.2.1-5 B 3.2.1-6 B 3.2.1-7 B 3.2.1-8 B 3.2.1-9 B 3.2.1-10 B 3.2.1-11 B 3.2.2-1 B 3.2.2-2 B 3.2.2-3 B 3.2.2-4 B 3.2.2-5 B 3.2.2-6 B 3.2.2-7 Amendment Revision 0 Revision 0 Revision 0 Revision 2 Revision 2 Revision 2 Revision 2 Revision 2 Revision 0 Revision 0 Revision 0 Revision 0 Revision 0 Revision 0 Revision 0 Revision 1 Revision 0 Revision 0 Revision 1 Revision 0 Revision 0 Revision 0 Revision 0 Revision 0 Revision 3 Revision I Revision 2 Revision 1 Revision 1 Revision 1 Revision 1 Revision 1 Revision Date 9/30/98 9/30/98 9/30/98 1/08/04 1/08/04 1/08/04 1/08/04 1/08/04 9/30/98 9/30/98 9/30/98 9/30/98 9/30/98 9130198 9/30198 10/02/00 9/30/98 9130198 10/02/00 9/30/98 9/30/98 9/30198 9/30/98 9/30/98 10/01/02 3/01/00 10/02/00 3/01/00 3/01/00 3/01/00 3/01/00 3/01/00 I

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Catawba Units 1 and 2 Page 14 1/8/04

Rod Position Indication B 3.1.7 B 3.1 REACTIVITY CONTROL SYSTEM B 3.1.7 Rod Position Indication BASES BACKGROUND According to GDC 13 (Ref. 1), instrumentation to monitor variables and systems over their operating ranges during normal operation, anticipated operational occurrences, and accident conditions must be OPERABLE.

LCO 3.1.7 is required to ensure OPERABILITY of the control rod position indicators to determine control rod positions and thereby ensure compliance with the control rod alignment and insertion limits.

The OPERABILITY, including position indication, of the shutdown and control rods is an initial assumption in all safety analyses that assume rod insertion upon reactor trip. Maximum rod misalignment is an initial assumption in the safety analysis that directly affects core power distributions and assumptions of available SDM. Rod position indication is required to assess OPERABILITY and misalignment.

Mechanical or electrical failures may cause a control rod to become inoperable or to become misaligned from its group. Control rod inoperability or misalignment may cause increased power peaking, due to the asymmetric reactivity distribution and a reduction in the total available rod worth for reactor shutdown. Therefore, control rod alignment and OPERABILITY are related to core operation in design power peaking limits and the core design requirement of a minimum SDM.

Limits on control rod alignment and OPERABILITY are established in LCO 3.1.4, 'Rod Group Alignment Limits," and all rod positions are monitored and controlled during power operation to ensure that the power distribution and reactivity limits defined by the design power peaking and SDM limits are preserved.

Rod cluster control assemblies (RCCAs), or rods, are moved out of the core (up or withdrawn) or into the core (down or inserted) by their control rod drive mechanisms. The RCCAs are divided among control banks and shutdown banks. Each bank may be further subdivided into two groups to provide for precise reactivity control.

The axial position of shutdown rods and control rods are determined by two separate and independent systems: the Bank Demand Position Indication System (commonly called group step counters) and the Digital Rod Position Indication (DRPI) System.

Catawba Units 1 and 2 B 3.1.7-1 Revision No. 0

Rod Position Indication B 3.1.7 BASES BACKGROUND (continued)

The Bank Demand Position Indication System counts the pulses from the Rod Control System that move the rods. There is one step counter for each group of rods. Individual rods in a group all receive the same signal to move and should, therefore, all be at the same position indicated by the group step counter for that group. The Bank Demand Position Indication System is considered highly precise (+/- 1 step or +/-- 5/8 inch). If a rod does not move one step for each demand pulse, the step counter will still count the pulse and incorrectly reflect the position of the rod.

The DRPI System provides a highly accurate indication of actual control rod position, but at a lower precision than the step counters. This system is based on inductive analog signals from a series of coils spaced along a hollow tube with a center to center distance of 3.75 inches, which is 6 steps. To increase the reliability of the system, the inductive coils are connected alternately to data system A or B. Thus creating two separate and independent systems (Data A and Data B). Also, the coils are not placed at the reflected six step increments starting at rod bottom.

Because of this arrangement, the nominal accuracy of the system is + 3 - l steps indicated versus true rod position. Due to mechanical positioning - i of the coils on the rod position detector and expansion in containment atmosphere, another + 1 step is added to system accuracy making it + 4 steps.

If one system fails, the DRPI will go to half accuracy. The accuracy will l

be - 10, + 4 steps when either Data A or Data B fails. Therefore, the maximum deviation between the group demand counters and DRPI could be 10 steps, or 6.25 inches.

Gray code (A & B data from the data cabinets in containment) is sent to the DRPI equipment in the control room. The gray code is processed by the DRPI equipment and the rod position is displayed on the control board. The gray code is also sent from the DRPI equipment to the Operator Aid Computer (OAC), where it is processed by the OAC and the rod position is displayed on the OAC. The processing of the gray code by the DRPI equipment and the OAC are completely independent.

Therefore, both the DRPI display and the OAC DRPI indication are considered valid indications of control rod position.

APPLICABLE Control and shutdown rod position accuracy is essential during power SAFETY ANALYSES operation. Power peaking, ejected rod worth, or SDM limits may be violated in the event of a Design Basis Accident (Ref. 2), with control or shutdown rods operating outside their limits undetected. Therefore, the acceptance criteria for rod position indication is that rod positions must be known with sufficient accuracy in order to verify the core is operating within the group sequence, overlap, design peaking limits, ejected rod Catawba Units 1 and 2 B 3.1.7-2 Revision No. 2

Rod Position Indication B 3.1.7 BASES APPLICABLE SAFETY ANALYSES (continued) worth, and with at least minimum SDM (LCO 3.1.5, "Shutdown Bank Insertion Limits," and LCO 3.1.6, mControl Bank Insertion Limits"). The rod positions must also be known in order to verify the alignment limits are preserved (LCO 3.1.4, "Rod Group Alignment Limits"). Control rod positions are continuously monitored to provide operators with information that ensures the plant is operating within the bounds of the accident analysis assumptions.

The control rod position indicator channels satisfy Criterion 2 of 10 CFR 50.36 (Ref. 3). The control rod position indicators monitor control rod position, which is an initial condition of the accident.

LCO LCO 3.1.7 specifies that one DRPI System and one Bank Demand Position Indication System be OPERABLE for each control rod. For the control rod position indicators to be OPERABLE requires meeting the SR of the LCO and the following:

a.

The DRPI System indicates within 12 steps of the group step counter demand position as required by LCO 3.1.4, "Rod Group Alignment Limits";

b.

For the DRPI System either Data A or Data B is OPERABLE for each rod; and

c.

The Bank Demand Indication System has been calibrated either in the fully inserted position or to the DRPI System.

The 12 step agreement limit between the Bank Demand Position Indication System and the DRPI System indicates that the Bank Demand Position Indication System is adequately calibrated, and can be used for indication of the measurement of control rod bank position.

A deviation of less than the allowable limit, given in LCO 3.1.4, in position indication for a single control rod, ensures high confidence that the position uncertainty of the corresponding control rod group is within the assumed values used in the analysis (that specified control rod group insertion limits).

These requirements ensure that control rod position indication during power operation and PHYSICS TESTS is accurate, and that design assumptions are not challenged.

OPERABILITY of the position indicator channels ensures that inoperable, misaligned, or mispositioned control rods can be detected. Therefore, Catawba Units 1 and 2 B 3.1.7-3 Revision No. 2

Rod Position Indication B 3.1.7 BASES LCO (continued)d power peaking, ejected rod worth, and SDM can be controlled within acceptable limits.

APPLICABILITY The requirements on the DRPI and step counters are only applicable in MODES 1 and 2 (consistent with LCO 3.1.4, LCO 3.1.5, and LCO 3.1.6),

because these are the only MODES in which power is generated, and the OPERABILITY and alignment of rods have the potential to affect the safety of the plant. In the shutdown MODES, the OPERABILITY of the shutdown and control banks has the potential to affect the required SDM, but this effect can be compensated for by an increase in the boron concentration of the Reactor Coolant System.

ACTIONS The ACTIONS table is modified by a Note indicating that a separate Condition entry is allowed for each inoperable rod position indicator per, group and each demand position indicator per bank. This is acceptable because the Required Actions for each Condition provide appropriate compensatory actions for each inoperable position indicator.

A.1 When one DRPI channel Data A and Data B per group fails, the position of the rod can still be determined by use of the incore movable detectors.

Based on experience, normal power operation does not require excessive movement of banks. If a bank has been significantly moved, the Required Action of B.1 or B.2 below is required. Therefore, verification of RCCA position within the Completion Time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is adequate for allowing continued full power operation, since the probability of simultaneously having a rod significantly out of position and an event sensitive to that rod position is small.

A.2 Reduction of THERMAL POWER to < 50% RTP puts the core into a condition where rod position is not significantly affecting core peaking factors (Ref. 4).

The allowed Completion Time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is reasonable, based on' operating experience, for reducing power to < 50% RTP from full power conditions without challenging plant systems and allowing for rod position determination by Required Action A.1 above.

Catawba Units 1 and 2 B 3.1.7-4 Revision No. 2

Rod Position Indication B 3.1.7 BASES ACTIONS (continued)

B.1 and B.2 These Required Actions clarify that when one or more rods with inoperable position indicators have been moved in excess of 24 steps in one direction, since the position was last determined, the Required Actions of A.1 and A.2 are still appropriate but must be initiated promptly under Required Action B.1 to begin verifying that these rods are still properly positioned, relative to their group positions.

If, within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, the rod positions have not been determined, THERMAL POWER must be reduced to

• 50% RTP within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to avoid undesirable power distributions that could result from continued operation at > 50% RTP, if one or more rods are misaligned by more than 24 steps.

The allowed Completion Time of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> provides an acceptable period of time to verify the rod positions.

C.1.1 and C.1.2 With one demand position indicator per bank inoperable, the rod positions can be determined by the DRPI System. Since normal power operation does not require excessive movement of rods, verification by administrative means that the rod position indicators are OPERABLE and the most withdrawn rod and the least withdrawn rod are

• 12 steps apart within the allowed Completion Time of once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is adequate.

Since DRPI is the only operable rod position indication, administrative means are actions taken by the control room SRO to assure that the DRPI for the affected bank remains operable at all times. These administrative means would prevent any maintenance or testing of the operable DRPI for the affected bank until the inoperable demand position indicator is returned to operable status.

C.2 Reduction of THERMAL POWER to

• 50% RTP puts the core into a condition where rod position is not significantly affecting core peaking factor limits (Ref. 4). The allowed Completion Time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> provides an acceptable period of time to verify the rod positions per Required Actions C.1.1 and C.1.2 or reduce power to

• 50% RTP.

Catawba Units 1 and 2 B 3.1.7-5 Revision No. 2

Rod Position Indication B 3.1.7 BASES ACTIONS (continued)

D.1 If the Required Actions cannot be completed within the associated Completion Time, the plant must be brought to a MODE in which the requirement does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. The allowed Completion Time is reasonable, based on operating experience, for reaching the required MODE from full power conditions in an orderly manner and without challenging plant systems.

SURVEILLANCE SR 3.1.7.1 REQUIREMENTS Verification that the DRPI agrees with the demand position within 12 steps ensures that the DRPI is operating correctly.

This Surveillance is performed prior to reactor criticality after each removal of the reactor head as there is the potential for unnecessary plant transients if the SR were performed with the reactor at power.

REFERENCES

1.

10 CFR 50, Appendix A, GDC 13.

2.

UFSAR, Section 15.0.

3.

10 CFR 50.36, Technical Specifications, (c)(2)(ii).

4.

UFSAR, Section 15.4.

I Catawba Units 1 and 2 B 3.1.7-6 Revision No. 2