ML20069E704
| ML20069E704 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 03/08/1983 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Sternberg D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, ANPP-23199-GHD, DER-82-69, NUDOCS 8303220161 | |
| Download: ML20069E704 (7) | |
Text
Docket Nos. 50-528/529/530 50.55(e),-Repprt
", ayip Arizona Public Service Company,_,,[,2;y f j, Po. box 21666. PHOENIX. ARIZONA 85036 "I
March 8, 1983 ANPP-23199%dD/BSK U. S. Nuclear Regulatory Commission Region V Creekside Oaks Office Park 1450 Maria Lane - Suite 210 Walnut Creek, California 94596-5368 Attention:
Mr. D. M. Sternberg, Chief Reactor Projects Branch 1
Subject:
Final Report - DER 82-69 A 50.55(e) Report Relating to Incorrectly Marked Fuses In Control Element Drive Mechanism Control System File:
83-019-025 D.4.33.2
Reference:
(A) Telephone Conversation between P. Narbut and G. Duckworth on November 24, 1982 (B) ANPP-22588, dated December 23, 1982 (Interim Report)
Dear Sir:
Attached is our final written report of the deficiency referenced above, which has been determined to be Not Reportable under the requirements of 10CFR50.55(e).
Very truly yours, L
C(R Tll E. E. Van Brunt, Jr.
APS Vice President Nuclear Projects Management ANPP Project Director EEVBJr/GIID:db Enclosures cc: See Attached Page 2 8303220161 830308 PDR ADOCK 05000528 U
U. S. Nuclear Regulatory Commission March 8, 1983 Attention:
Mr. D. M. Sternberg, Chief ANPP-23199-GHD/BSK Page 2 cc: Richard DeYoung, Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission' Washington, D. C. 20555 T. G. Woods, Jr.
J. A. Roadel D. B. Essnacht G. C. Andognini J. R. Bynum A. C. Rogers B. S. Kaplan W. E. Ide J. Vorees P. P. Klute/D. D. Green A. C. Gehr W. J. Stubblefield W. G. Bingham R. L. Patterson R. W. Welcher R. M. Grant D. R. Hawkinson L. E. Vorderbrueggen G. A. Fiorelli I
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-FINAL REPORT - DER 82-69 DEFICIENCY EVALUATION 50.55(e)
ARIZONA PUBLIC SERVICE COMPANY (APS)
PVNGS UNIT 1, 2 & 3 I.
DESCRIPTION OF DEFICIENCY Per Combustion Engineering (CE) Infobulletin 82-10, fuses used in the Digital Isolation Device Assembly (DIDA) should have a one (1) amp rating. CE has been notified by Rochester Instrument Systems (RIS) that fuses from their in-house inventory were discovered to have been labeled incorrectly. The fuses were manufactured by Federal Pacific Electric, Economy Fuse Division, Des Plaines, Iliinois. The fuse part r, umber is marked on the end caps and the luse rating is marked on the fuse container body. Approximately one to two percent of these fuses at RIS had "EBS-7A" stamped on the metal end of the fuse, although the fuse body label incorrectly indicated a one (1) amp rating.
These fuses are used by CE in the Digital Isolation Device Assembly (D1DA) which is part of the Control Ziement Drive Mechanism Control System (CEDMCS) Auxiliary Cabinets. These cabinets provide isolation of Class 1E and non-Class 1E circuits in accordance with Regulatory Guide 1.75.
In this application, fuses with a seven (7) amp rating rather than the intended one (1) amp rating would permit a fault current above that for which the DIDA has been analyzed or tested.
II.
ANALYSIS OF SAFETY IMPLICATIONS This condition is evaluated as not reportable. Based upon a review of the circuit design by CE, the circuit with the seven (7) ampere fuse is sufficient to prevent a credible fault from cascading through the DIDA. This judgement is based upon the inherent coil to contact isolation of the relay and upon the fact that sufficient energy would have to be provided to the input side of the relay to breach the isolation of the RSPT contact to the RSPT voltage divider. The inherent isolation provided by the following design features preclude the condition from constituting a safety significant condition:
physical / electrical separation within the RSPT o
physical / electrical separation provided by the DIDA relay o
fault interruption capability of the seven (7) amp fuse o
physical / electrical isolation of the CEDMCS input relays o
III. CORRECTIVE ACTION The corrective action, per CE letter V-CE-17696 (attached),
consists of replacing existing seven (7) amp fuses in the DIDA with one (1) amp fuses. CE's FAR Nos. 14273-553 (Unit 1), 14373-288 (Unit 2) and 14473-82 (Unit 3) have been issued to direct the remedial activities.
C.E Power Systems Tel 203/6881911 Cornbustion Engineering inc.
Telex 99297 1000 Prospect Hill Road Winasor. Connecticut 06095 POWER
=; SYSTEMS
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ww January 12, 1983 g, g g V-CE-17696 g. g, y._
JM1 ?'83 Mr. W. G. Bingham Bechtel Power Corporation i
37 12400 East Imperial Highway i
m wn,
-z Norwalk, California 90650 72; W.M i j~
Subject:
Arizona Nuclear Power Project 7
m-j Rochester Instruments Digital a
i Isolation Device Assembly EYE Manufacturing Deficiency c,3 CW%$
Reference:
B/CE-E-42634 dated November 23, 1982
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Enclosure:
Figure 1 E."MP J
Dear Mr. Bingham:
rc
- w c r. e m c The purpose of this letter is to respond to the reference and assas7 7#4 the reported deficiency in the Rochester Instrument System Digital N
I Isolation Device Assembly (DIDA). This assessment has two parts, an assessment of the recommended corrective action and an assessment of the reporting responsibilities.
The corrective action consists of replacing existing 7 amp fuses in i
the DIDA with I amp fuses.
The DIDA provides isolation between the " associated circuits" (RG 1.75 definition) of the Reed Switch Position Transmitters (RSPT) and the non-class IE Control Element Drive Mechanism Control System. Figure (1) provides a simplified schematic overview of the systems involved and their interconnections.
l The RSPT assembly provides two functions, a Class 1E input function that indicates CEA position to the Core Protection Calculators and a non-Class IE function that provides control interlocks and position indication to the CEA control system. Because of the close physical proximity of the two sensing elements in the RSPT assembly and in the cable inside the containment, the control interlock circuits are " associated" by the definition of Regulatory Guide 1.75 and must be treated as Class IE circuits until they are downgraded to non-Class IE by means of a " qualified" isolator.
~
- ,j Mr. W. G. Bingham January 12, 1983 V-CE-17696 Page 2 i
The Digital Isolation Device Assembly (DIDA) provides the " qualified" isolation necessary to downgrade the circuit classification to non-1E prior to being utilized in the non-class IE control system.
The DIDA was designed to provide circuit and fault isolation by utilizing an amplifier driven relay whose contact outputs provide the isolated function. A fuse is provided to assure interruption of fault currents that might emanate from the CEDMCS or from the non-class IE cable run.
The DIDA was designed and qualified with one ampere fuses as the fault interruption device. The vendor notified C-E that 7 ampere fuses may have been inadvertently utilized in place of the required 1 ampere fuses i
through a mis-labeling error by the fuse manufacturcr. The DIDA manufacturer (RIS) states that approximately 1-2% of the fuses had been mislabeled.
The 7 ampere fuse would permit a fault current above that for which the DIDA has been analyzed or tested.
Based upon a review of the circuit design, the circuit with the 7 ampere fuse is sufficient to prevent a credible fault from cascading through the DIDA. This judgement is based upon the inherent coil to contact isolation of the relay and upon the fact that sufficient energy would have to be provided to the input side of the relay to treach the isolation of the RSPT contact to the RSPT voltage divider.
Pr.ior to the issuance of R.G.1.75 this circuit in fact did not contain a DIDA assembly.
In ANO-2 class plants, the RSPT contact was cabled separately at the containment penetrations and routed directly to the CEDMCS. The design received a great deal of Regulatory scrutiny on ANO-2 and was deemed adequate.
The DIDA was added to address licensing and comercial issues revolving around the increased separation requirements mandated by Reg. Guide 1.75 and comitted to by CESSAR for SYS80 class Plant.
The inherent isolation provided by the
- 1) physical / electrical separation within the RSPT
- 2) physical / electrical separation provided by the DIDA relay
- 3) fault interruption capability cf the 7 amp fuse
- 4) physical / electrical isolation of the CEDMCS input relays is sufficient such that the defect is not reportable.
Mr. W. G. Bingham January 12, 1983 Page 3 V-CE-17696 In C-E's opinion, this item is not reportable under the requirements of 10CFR50.55(e) or 10CFR Part 21. C-E's evaluation was performed in accordance with our Quality Assurance of Design Manual as indicated by FAR No.14273-553 (Unit 1), FAR No.14373-288 (Unit 2) and FAR No. 14473-82 (Unit 3). These documents are available for review at the C-E Windsor Office.
In you have any further questions, please do not hesitate to call.
Very truly yours.
hrp thf6 C. Ferguson Project Manager CF/mg Enclosure cc: Messrs:
E. E. Van Brunt, Jr., w/e G. C. Andognini - w/e J. Vorees - w/e W. H. Wilson R. H. Holm J. W. Dilk G. A. Butterworth S. N. Mager D. B. Amerine - w/e W. L. MacDonald J. R. Bynum e
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