ML20128D504
| ML20128D504 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 02/02/1993 |
| From: | Tuckman M DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9302100165 | |
| Download: ML20128D504 (6) | |
Text
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,' - 1; 3 Duke Itmer Company Vice President
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^ Catau+a Nuclear Ger:emtion Department:._
&I S. TLuwtx 4800 Conrord Road *
($03)S3IJ20S 0flice.
- hrk;SC29745 (803}8313426 fax 1 ~
DUKEPOWER
- February 3,1993 U.S. Nuclear Regulatory Commission-ATTN:? Document Control Desk Washington, D.C. 20555
' Catawba Nuclear Station -
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Subject:
3 Docket Nos 50-413 and 50-414
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Reply To A Notice Of Violation NRC Inspection Report 50-413/ 92-29 and 50-414/92,
Attached is Duke Power's response to the Level IV; violation cited in the Notice of =
Violation by subject inspection Report dated ' January 6,1993. -
The violation involved design deficiencies regarding the interactio'n'of. non safety related equipment with safety-related control: circuitry whichLcouldLaffect the.
operation of both units' Turbine Driven Auxiliary Feedwater Pumps (TDAFWPs).-
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- Very truly yours, C.
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M.S. Tuckman -
1 IJLL/_-
-Attachment
'9302100165 930202
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' U.6. Nuclear Re0ulatory Commission i
February 3,1993 Page 2 l
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S.D. Ebneter Regional Administrator, Region ll R.E. Martin, ONRR W.T. Orders Senior Resident inspector
DUKE POWER COMPANY REPLY TO A NOTICE OF VIOLATION 413/414,92-29 01 10 CFR 50, Appendix B, Criterlon lil, Design Control, and the licensee's accepted Quality Assurance Program (Duke-1-A, Section 17.3.2.2) collectively require that -
measures be established to assure that applicable regulatory requirements and the design basis specified in the license application for the facility be correctly translated into specifications, drawings, procedures and instructions. Further, design control measures are to provide for verifying the adequacy of design, by the performance of design reviews, the use of alternate or simplified calculational methods, or the performance of a suitable testing program.
Technical Specification 3.7.1.2 requires at least three Auxillary Feedwater (CA) pumps and associated flow paths be operable in Modes 1-3. Operability includes the capability of the system to perform its intended safety function during design basis events, assuming a single active failure, and with no credit taken for non safety equipment toward mitigating the event.
Contrary to the above, design control measures associated with the CA System were inadequate in that design deficiencies existed on both units since startup which rendered the systems inoperable in that they were not capable of performing their intended safety functions. The design deficiencies involve interaction of non-safety-related equipment with safety related control circuitry affecting the operation of both units' Turbine Driven Auxiliary Feedwater Pumps (TDAFPs) such t'.at during certain design basis events, malfunction of the non-safety related equipment, coupled with a single active failure would have prevented the CA Systems of both units from delivering the required flow to two intact S/Gs as designed.
This is a Severity LevelIV Violation, 1
DUKE POWER COMPANY REPLY TO A NOTICE OF VIOLATION 413/414,92-29-01
RESPONSE
1.
Reason For Violation The events which led to this violation were initiated by a design analysis that discovered an improper interaction of systems and/or components.
The Catawba Design Basis requires that the CA System withstand an initiating event along with a single active failure and still meet the minimum core cooling requirements. However, originaldesign for the CA Turbine Driven Pump did not meet the single failure criteria for the two accident scenarios described in this report. The design deficiencies were not detected during the design basis documentation process in that the DBD program scope does not require a 100% verification of as built circuits.
2.
Corrective Actions Taken and Results Achieved A)
On December 1,1992, at 7:30 p.m., both Unit 1 and Unit 2 CA Turbine Driven Auxiliary Feedwater Pumps (TDAFPs) were declared inoperable when it was determined that a non-vital, non-safety related DC power supply affected CA system operability. Unit 1 was placed in a six (6) hour action statement due to an existing inoperability of CA Motor Driven Pump 1 A and Unit 2 was placed in a seventy two (72) hour action statement under Technical Specification - 3.7.1.2 (Auxiliary Feodwater System).
On December 2,1992, at 1:15 a.m., a Temporary Station Modification (TSM) was installed on 'Jnit 1 to restore the Unit 1 CA TDAFP to operability. The TSM involves wiring a jumper across an open contact on the safety related side of the CA TDAFP suction swap circuit in order to simulate a continuous CA TDAFP running logic. This ensures that the auto-swap will occur upon receipt of the CA Auto Start Signal and CA TDAFP Low Suction Pressure condition, regardless of any failures within the non-safety portion of the circuit. Three hours later, an identical TSM was installed on Unit 2 and subsequently CA TDAFP 2 was declared operable.
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DUKE POWER COMPANY-REPLY TO A NOTICE OF VIOLATION 413/414,92-29 01 2
B)
A review of other CA System circuits was initiated to assure that no other control system interaction deficiencies existed. On December 8,-
4 1992, at 3:50 p.m., it was determined that a failure of Solid State Protection System (SSPS) Train A made the CA TDAFP speed control l
i dependent on a non-safety circuit. Consequently, Unit 1 -& 2.CA TDAFPs were declared inoperable. On December 9,,1992, at 2:00 a.m., a TSM.
was installed on both units to restore both CA TDAFPs to operable status. The TSM Involved removing power to the CA TDAFP speed control solenoid valve, thereby, forcing the governor to maximum speed--
i setting and disabling the non-safety speed control circuitry.- Both CA-TDAFPs were declared operable following successful retest.
i 3.
Corrective Actions To Be Taken To Avoid Further Violations A)
TSMs-- Installed on-the CA TDP auto-swap' circults will be-made permanent so that the CA TDP suction auto-swap to the safety related suction source will be initiated by the CA Auto Start Signal and the CA TDP Low Suction Pressure conditions only. The TSMs _for Unit:1 and.
Unit 2 will be replaced with the_ permanent modifications by U1EOC8 (May 3,1995) and U2EOC7 (January 5,-1996), respectively.
p B)
An evaluation is underway to determine. If a Train B CA TDP speed contrcl circuitry will.be implemented to provide a signal to= fail the CA TDP to maximum speed or if the TSM which forces the governor-to
---maintain maximum speed setting will be made permanent. One of the two actions for Unit 1 and Unit 2 will be accomplished by U1EOC8 (May 3,1995) and U2EOC7 (January 5,1996), respectively.-
In addition _ to_ making the TSMs permanent,' a review of Duke designed sa.fety :
related process systems is being conducted by the System Engineering and-Instrurnentation & Electrical Engineering groups. This review will look for cross
- train interactions in the control systems and dependence of safety circuits upon non-safety circuits and will be completed by May 1,1993.
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4 DUKE POWER COMPANY REPLY TO A NOTICE OF VIOLATION 413/414,92-29-01 1
4.
Date Of Full Comoliance i
Duke Power is now in ful! compliance.
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