ML20093L539
| ML20093L539 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 10/15/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Deyoung R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| EA-84-025, EA-84-25, NUDOCS 8410190050 | |
| Download: ML20093L539 (3) | |
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TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374ot 400 Chestnut Street Tower II October 15, 1984 Mr. R. C.-DeYoung, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Dear Mr. DeYoung Please refer to J. A. Domer's letter to you dated August 20, 1984 which transmitted our response to Notice of Violation and Proposed Civil Penalty:
EA-84-25 for our Browns Ferry Nuclear Plant (Reference Inspection Reports 50-259/83-46, -260/83-46, -296/83-46, 50-259/83-55, -260/83-55, -296/83-55, 50-259/84-01, -260/84-01, and -296/84-01). As a result of discussions with the NRC Site Resident Inspector, we are enclosing a revised response to Item I.D(2).
'f. you have any questions, please : call Jim Domer at FTS 858-2725.
To thebest of my knowledge,-I declare the statements contained herein are complete and.true.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Licensing Enclosure cc (Enclosure):
U.S. Nuclear Regulatory Commission Region II ATTN: James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. R. J. Clark Browns Ferry Project Manager U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20814
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~ ENCLOSURE s<
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Contrary to the above, Engineering Design (EN DES) Engineering Procedure (EP) 1.48 issued December 16, 1983, allowed decisions to be made for a significant-nonconforming condition without design control measures commensurate with those applied to the original
- - de sign.. In consequence, 16 emergency diesel-generator cooling heat exchangers and 12 residual heat removal (RER) pump seal cooling heat exchangers were not targeted for prompt corrective action applying the guidance from EN DES-EP 1.48, 1.
Admission or Denial of the A11eaed Vloistion TVA admits the violation occurred.
~2.
Reasons for the Violation if Admitted Reason for Vioistion I.D(1) - The BFN units 1 and ?. heat exchangers were supplied with the diesel generators packages as part of the nuclear steam supply' system (NSSS) purchased in 1966 from General Electric (GE). The unit 3 diesel generators were contracted for by TVA in 1973, to the same specifications as those for units 1 j.
and 2.
TVA, in designing the EECW, assumed that the equipment being supplied by GE that utilized 3ECW was rated for operation at the EECW system pressure. As such, this interf ace was overlooked at the design review stage.
i I.
I.D(2) - The diesel generator EECW heat exchanger design deficiency was originally identified by nonconformance report (NCR)
BFNNEB8301. This NCR was later superseded by NCR BFNBWP8311
.which identified similar problems with other EECW ' users' including the residual heat removal (RHR) pump seal coolers.
l Failure evaluation / engineering reports (FE/ERs) provided in accordance with EN DES-EP 1,48 as part of these NCR
. transmittals supplied engineering evaluations of these i
conditions to assist in the determination of the condition's i
reportability to NRC. The FE/ER also provides (when l
available) recommendations - for corrective actions. However, implementation of corrective actions is accomplished not by i
the issuance of FE/ERs but through the existing design change reque st (DCR)/ engineering change notice (ECN) process. As
-such, it is our position that the FE/ER is not a part of TVA's design change control process.
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For the diesel generator EECW heat exchangers, it was determined that f ailure of the heat exchangers at the maximum system operating pressure was unlikely. This assessment was based on engineering analysis of the heat exchanger c
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subcamponents, a successini hydrostatic test of the heat exchangers at a pressure above the maxiuna system operating pressure, and the previous years of satisfactory service from the heat exchangers at Browns Ferry Nuclear Plant (BFN). As
'a resnit, modifications to the EECW for reducing the system pressure at the heat exchanger inlet to.the design pressure of the diesel generator heat exchangers were implemented on a schedule that was considered timely by IVA and yet did not perturbate ongoing work of equal or greater priority at BFN.
_I. As for the'RHR pump seal cooler heat exchangers, TVA had begna replacing the original heat exchangers with a newer model. (same 150 lb/in2g. design pressure) when the EECW design pressure discrepancy was identified. However, it was determined that even.though the EECW system design pressue was higher than the rated pressure xor these heat exchangers (both the origional and new models), the actual EECW system pressure at the heat exchangers was lower than the heat exchanger design pressure (note that-the EECW system pressure at the diesel generator heat exchangers was higher than the heat exchanger design pressure). Also, the manufacturer of the new heat exchangers certified to TVA that the heat exchangers were qualified for service at the EECW system 2
design pressure of 185 lb/in28 Hence, corrective actions for this condition involve changes in design documentation only. Replacement of the RER pump se'al cooler heat
- exchangers has been scheduled by TVA in a manner such that previously scheduled work of equal or greater priority would not be adversely impacted.
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3.
Corrective Stoos Which Have Been Taken and Results Achieved ECN P0709 was initiated in November 1983 to install throttling valves L
in the EECW supply to the diesel-generator heat exchangers to reduce the EECW system operating pressure at the heat exchangers. As of July 1984, all of the throttling valves have been installed and tested.
l As noted above, the RER seal ecolor heat exchangers are being replaced i
by new heat exchangers that are gyalified for operation at the EECW system design pressure (185 lb/in g).
Per L. M. Mills' letter to J. P. O'Reilly dated February 1,1984, the new heat exchangers have been installed on units 1 and 3, 1
These modifications will require some minor changes to the information on these systems and components in the Browns Ferry Final Safety Analysis Report (FSAR).
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