PLA-1027, Final Deficiency Rept Re Violation of Separation/Isolation Criteria for Class IE Electrical Equipment.Procedure FP-E-10 & Drawings E-396 & E-60 Developed to Reflect Current SAR Commitments.Also Reported Per 10CFR21
| ML20042A632 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 03/15/1982 |
| From: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-PT21-82 10CFR-050.55E, 10CFR-50.55E, PLA-1027, NUDOCS 8203230629 | |
| Download: ML20042A632 (7) | |
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@ Pennsylvania Power & Light Company Two North Ninth Street
- Allentown, PA 18101 + 215 / ?70 5151 I
I Norman W. Curtis Vice President-Engineering & Construction-Nuclear 215 / 770-5381 March 15, 1982 Mr. R. C. Haynes i
Director, Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
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SUSQUEllANNA STEAM ELECTRIC STATION FINAL REPORT OF DEFICIENCIES REGARDING y'.
VIOLATION OF SEPARATION /ISCLATION CRITERIA T'
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FOR ELECTRICAL EQUIPMENT
_ [gg i ERs 100450/100508 FILES 840-4/900-10/821-10 fc-Q 7M
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PLA-1027 1
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References:
PLA-420
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PLA-426
,i7 PLA-474 PLA-576 i
Dear Mr. Haynes This letter serves to provide the Commission with a final report for a series of related deficiencies, each of which represented a violation of separation /
isolation criteria for Class lE Electrical Systems as defined in the Susquehanna Safety Analysis Report. PP&L has evaluated each of these deficiencies as they were identified through a special program undertaken for that purpose. This evaluation has resulted in certain of these deficiencies being reported under 1
the provisions of 10 CFR 50.55(e) to NRC in correspondence identified as PLA-420, PLA-426, PLA-474 and PLA-576. The deficiencies previously reported involve the 4.16 KV Safeguard Switchgear and other vendor supplied electrical panels.
Certain ot the deficiencies, previously reported to NRC under the provisions of 10 CFR 50.55(e), have now been fully analyzed and PP&L has concluded that they are not reportable. These are discussed in the attached Final Report under Section II of the Conclusions.
Specific deficiencies previously reported to NRC which have been confirmed as reportable under the provisions of 10 CFR 50.55(e) are:
e The deficiency regarding the electrical synchronizing circuit in the 4 KV switchlear as documented on Nonconformance Report (NCR) 4277.
e The deficiency in the GE supplied electrical control room panel 1C601 as documented on Nonconformance Report (NCR) 4277.
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March 15, 1982 SSES PLA-1027 ERs 100450/100508 Files 840-4/900-10/
821-10 The attached Final Report provides a description of these specific deficiencies, their cause, safety implications, and the corrective action.
The cause and corrective action described in this report are comprehensive in their applicability to both those deficiencies identified as reportable herein and those which have been determined to be not reportable.
Since the details of this report provide information relevant to the reporting requirements of 10 CFR 21, this correspondence is considered to also discharge any formal responsibility PP&L may have in compliance thereto.
We trust the Commission will find this report to be satisfactory.
Very truly yours,
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}\\0 N. W. Curtis Vice President-Engineering & Construction-Nuclear JBW:sab Attachment cc:
Mr. Richard C. DeYoung (15)
Director - Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D.C. 20555 1
1 Mr. G. Mcdonald, Director (1)
Office of Management Information & Program Control U.
S. Nuclear Regulatory Commission Washington, D.C. 20555 l
Mr. Gary Rhoads U. S. Nuclear Regulatory Commission P.O. Box 52 Shickshinny, PA 18655
SSES PLA-1027 ERs 100450/100508 Files 840-4/
Attachment to PLA-1027 FINAL REPORT 900-10/821-10
Subject:
Failure to comply with separation / isolation criteria applicable to vendor supplied Class lE Equipment.
Description of the Problem:
In 1979, during regular quality control inspection of installed vendor supplied electrical equipment at the Susquehanna Steam Electric Station (SSES), various departures from the requirements of SSES Separation Specification, Bechtel Notes &
Details Drawing E-60, were detected and documented in Non-Conformance (NCR) 4277.
In addition, engineering reviews by PP&L led to the identification of additional separation / isolation deficiencies which were subsequently documented on MCAR l-38.
Specifically, those deficiencies now confirmed as being reportable are:
1) violation of separation criteria for the internal wiring of the 4.16 KV switchgear and, 2) violation of separation criteria for BOP wiring by GE-NEBO in control room panel 1C601 manufactured by GE-NEBO.
r Cause of Deficiencies:
The cause of these deficiencies is considered to be failure of the principal design organization to systematically incorporate evolving SAR requirements for the separation / isolation of Class lE circuits into certain design output documents which governed the design and manufacture of various vendor supplied Class lE equipment.
The Susquehanna Plant design is committed to IEEE 279-1971 through the Preliminary Safety Analysis Report (PSAR) as docketed in 1971. With the evolution of industry and NRC guidance for the separation / isolation of Class lE Circuits, the Susquehanna SAR was revised in 1975 to incorporate commitments to Regulatory Guide 1.75 and IEEE 384 subject to clarifications and exceptions as outlined in the SAR.
These clarifications and exceptions were incorporated into the SAR to provide recognition that by 1975 the design of the Susquehanna electrical safety protection systems was nearly complete and that in the case of Susquehanna, full compliance with Regulatory Guide 1.75 - 1975 would not be a licensing requirement.
As the electrical system designs for Susquehanna were essentially complete prior to issuance of NRC and industry guidance for separation / isolation, the large majority of purchase specifications issued for Susquehanna did not reflect specific requirements for the separation of equipment internal wiring.
Although these separation / isolation requirements fer equipment internal wiring were subsequently incorporated into purchase and installation specifications and f
drawings, their incorporation was not sufficiently systematic or timely to preclude the deficiencies cited in this report.
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. SSES PLA-1027 ERs 100450/100508 Files 840-4/900-10/
821-10 Analysis of Safety Implications:
An engineering analysis was made on a case-by-case basis of the multiple separation violations identified by Bechtel in MCAR l-38, NCR-4277 and the Bechtel program described under the Corrective Action section of this report to determine if any of these violations represented a condition, which if it had remained uncorrected, would have adversely affected the safety of operations of this nuclear plant. This analysis was based on the single failure criterion that the Engineered Safety Feature (ESF) system must satisfy. This analysis has identified the following two deficiencies as reportable under 10 CFR 50.55(e).
A.
The deficiency involving non-Class lE wiring in contact with C] ass lE wiring is applicable to the 4.16 KV switchgear.
In the 4.16 KV swit
- sar, a common mode failure could occur due to this type of deficiency.
In m.e switchgear, a potential transformer energizes the bus undervoltage and sequence permissive relays and, at the same time, is connected to the control panel oC653 at the synchronizing board via a non-Class lE cable. The non-Class lE cables of all four switchgear lineups are routed in a common raceway. Hence, a failure involving a multiple short and/or open circuit of cables in a raceway due to a fire could de-energize one or more of the undervoltage and sequence permissive relays of the four Class lE 4.16 KV buses. This would result in load shedding and a trip of the incoming breaker or breakers. The alternate breaker or breakers would then close and trip. Eventnully the diesel generator breaker or breakers would close. The motor loads, however, would not reclose since the sequence permissive relay or relays would be de-energized.
Deficiencies involving Non-Class lE wiring in contact with Affiliated wiring of different channels or divisions not separated by at least 6 inches or a suitable physical barrier could result in a potential disabling of two channels of the 125 Vdc Class lE power supplies.
This is possible only in the Channel C and D 4.16 KV switchgear. Channel C switchgear supplies power to both Channel C and Division I loads. Channel C
- snnel C distribution panel and control power is supplied by a 125 V>-
Division I control power is supplied ircrc a similar panel of Channel A.
Wiring for Channel A and Division I control circuits are not separated from each other nor from non-Class lE 120/208 Vac 3-phase wires for space heaters. Assuming a type of failure involving a multiple short and/or open circuit of wires with a spatial distance of less than 6 inches inside a piece of equipment due to a single event, a disabling of Channels A and C distribution panels or batteries could occur. The case considered here is one in which the 125 Vdc wires of each channel are parallel with one phase of the 208 Vac space heater wiring.
The fault current could either trip the distribution panel main breaker or discharge the battery depending on the magnitude of the fault resistance. This is not acceptable, as this could disable the Channels A and C switchgear and diesel generators. With only Channel B and D power supplies available, the minimum emergency reactor core cooling loads during the worst case LOCA could not be supplied.
. SSES PLA-1027 ERs 100450/100508 Files 840-4/900-10/
821-10 The above analysis is also applicable to Channel D switchgear.
In this case, Channel B and D batteries could be simultaneously disabled.
As described above, the non-compliance with the separation criteria in the four 4.16 KV 'witchgear represents a design deficiency that could have an adverse effect on the safety of plant operations if left uncorrected. Hence, the non-compliance is reportable to the NRC under 10 CFR 50.55(e).
B.
GE supplied panel 1C601-16C has wiring for CRD Water Pump 1A and 1B.
GE has considered these as non-Class lE, which is in agreement with their elementary diagram. This wiring is for control switches to operate the 125 volt circuit which trip and close the 4.16 KV circuit breakers to stop and run the motors. The AC power system does not have a 4.16 KV non-Class lE bus; therefore, these two pumps were added to the Class lE bus.
Pump 1A was connected to 4.16 KV bus lA201 and its corresponding 125 Vdc controle are Affiliated to the Channel A/ Division I battery. Pump 1B was connected to 4.16 KV Bus lA204 and its corresponding 125 Vdc controls are Affiliated to the Channel B/ Division II battery. The pump 1A and 1B switch wiring is on the same terminal block side-by-side.
In addition, the internal wiring from the terminal block is routed in a common wire bundle through a single plug / jack to the respective side-by-side control switches.
The result of this is similar to the analysis of the 4.16 KV switchgear itself (Ref. Analysis A).
Assuming a type of failure involving a multiple short and/or open circuit of wires with a spatial distance of less than 6 inches due to a sihgle event, the potential may exist for disabling the 125 Vdc Channels A/I and B/II distribution panel main breakers or discharging the battery depending on the magnitude of the fault resistance. This is not an acceptable result, as this could disable Channels A/I and B/II switchgear and diesel generators.
With only Channels C and D power supplies available, the minimum emergency reactor core cooling loads during the worst LOCA cannot be supplied. Multiple short or open circuits in a raceway due to a fire will not cause the two channels to fail because all the cabling is provided in a redundant raceway.
As described above (Cause B), the non-compatibility of the GE and Bechtel separation criteria for the CRD Water Pump Controls in IC601-16C represents a design deficiency and could have an adverse effect on the safety of plant operations if left uncorrected. Hence, the noncompliance is reportable to the NRC under 10 CFR 50.55(e).
Deficiencies A and B above also represent nonconformances to current FSAR commit-ments to Regulatory Guide 1.75, which on further analysis, do represent violations of the single failure criteria of lEEE 279-71.
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Corrective Action:
l Bechtel Engineering has updated the project design documents to reflect current
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project separation and isolation SAR commitments. To assure compliance with these revised documents, Bechtel has developed a program for final inspection and acceptance of the specified provisions for electrical separation and isolation. This program is now defined by Bechtel Dwgs. E-396, E-60 and Bechtel Field Procedure FP-E-10.
. SSES PLA-1027 ERs 100450/100508 Files 840-4/900-10/
821-10 To assure that all electrical equipment that might have a separation violation would be identified for the subject inspection, Bechtel Engineering developed a computer listing of all electrical equipment that contained at least one terminated Class lE cable or through which Class lE cables passed without terminating. All equipment on this listing was to be subject to an engineering review and a field inspection to identify and document separation deficiencies found. Design and hardware deficiencies noted were to be referenced on this same computer listing as well as the means for correcting such deficiencies.
This computer listing was to be periodically updated using the master circuit schedule to incorporate design changes which may have created the need for additional reviews and inspections to assure that separation is maintained. Each revision of i
the computer listing would identify equipment and associated cables when cables were added or deleted. This computer listing includes all equipment supplied by Bechtel and GE-NEBO.
The following information was to be contained in the successive revisions of this computer listing:
Reference to the specific rework document for required internal wiring e
changes.
e A tabulation of cables exempt from separation requirements (e.g., annunciation and computer circuits).
o Identification of design scope (i.e., BOP or NSSS) for cables that terminate in GE supplied panels.
e Reference to the separation criteria applicable to each cable in the GE panels (i.e.,Dwg. E-60 or GE-NEDO).
Identification of cables in the majority Division / Channel in the larger e
panels.
PP&L and Bechtel Engineeringhave completed their review of Unit 1 and Common equipment on this computer listing and has documented the corrective action necessary to achieve compliance with separation / isolation requirements. Bechtel Engineering's review of Unit 2 equipment is in progress.
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Conclusion:==
I.
Reportable deficiencies The separation non-compliances identified previously represent deficiencies in the final design as approved and issued for the procurement of Class lE vendor supplied equipment.
Specific non-compliances determined to be reportable under the provisions of 10 CFR 50.55(e) are identified and elaborated upon in the " Analysis of Safety Implications" section of this report. The cause of the reportable deficiencies is considered to be failure of the i
principal design organization to incorporate in a timely manner, licensing commitments for the separation / isolation of Class 1E equipment internal wiring.
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r 5-SSES PLA-1027 ERs 100450/100508 Files 840-4/900-10/
821-10 i
A comprehensive corrective action program was developed by PP&L and Bechtel and implemented in the field to inspect, schedule, and monitor rework necessary to correct all separation non-compliances noted. This program also extends to Unit 2 equipment. Further, this program provides the basis for maintaining l
sepe. ration requirements as design changes are made.
II. Non-reportable deficiencies PP&L identified a condition in the system for isolating Non-Class lE loads i
connected to the 250 Vdc Class lE systems as reportable under the provisions of 10 CFR 50.55(e) in a letter PLA-420 dated November 14, 1979 from N. W. Curtis of PP&L to B. H. Grier of the NRC (NRC #190008). This design deficiency is documented on PP&L Deficiency Report DR-0134 and Bechtel MCAR 1-38 which contains an analysis as to why this deficiency is now considered not reportable to NRC.
In addition, a deficiency concerning separation criteria for the space heater power supply circuits in the Unit #1 4.16 KV switchgear.and vendor supplied electrical panels was identified as reportable to Mr. R. Gallo, NRC Resident Inspector by Mr. A. P. Sabol of PP&L during a telephone conversation on November 21, 1979. This conversation was later confirmed in a letter PLA-426 dated November 29, 1979 from N. W. Curtis of PP&L to Mr. B. H. Grier of the NRC (NRC #790010). This deficiency is also documented on Bechtel MCAR l-38 and PP&L Deficiency Report DR-0135 which contains an analysis as to why this deficiency is now considered not reportable to NRC.
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