United States Nuclear Regulatory Commission - Protecting People and the Environment


ACCESSION #: 9801220103

                       LICENSEE EVENT REPORT (LER)



FACILITY NAME:  Clinton Power Station                     PAGE: 1 OF 5



DOCKET NUMBER:  05000461



TITLE:  Incorrect Cable Resistance and Brake Horsepower Data Used

        in the Design Divisions 1 and 2 Emergency Diesel

        Generator Vent Fans Results in Design of Fan Motors Being

        Outside the Design Basis of the Plant



EVENT DATE:  09/29/96   LER #:  97-034-00   REPORT DATE:  01/16/98



OTHER FACILITIES INVOLVED:                          DOCKET NO:  05000



OPERATING MODE:  5   POWER LEVEL:  000



THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR

SECTION:

50.73(a)(2)(ii), OTHER



LICENSEE CONTACT FOR THIS LER:

NAME:  A.B. Haumann, Nuclear Engineering    TELEPHONE:  (217) 935-8881,

       Department                                       Extension 4078



COMPONENT FAILURE DESCRIPTION:

CAUSE:      SYSTEM:       COMPONENT:       MANUFACTURER:

REPORTABLE NPRDS:



SUPPLEMENTAL REPORT EXPECTED:  YES EXPECTED SUBMISSION DATE 03/19/98



ABSTRACT:



Station engineers determined that during degraded voltage conditions, the

Divisions 1 and 2 emergency diesel generator (EDG) room vent, fans could

cause offsite power supply breakers to trip on undervoltage during

transient electrical bus loading conditions associated with a Lose of

Coolant Accident (LOCA) block start.  Improper cable resistance values

and brake horsepower ratings were used in the original design of the

Divisions 1 and 2 EDG vent fans.  The cable resistance values, provided

by Sargent & Lundy, did not account for the fans' "tin-coated" copper

conductor cables which have a higher resistance than uncoated conductor

cables.  Additionally, the brake horsepower of the fan motors was based

on an operating temperature of 96 degrees Fahrenheit (F).  The Divisions

1 and 2 EDG room vent fans are required to operate at temperatures below

96 degrees F and thus higher than originally calculated brake horsepower

is required for proper operation.  The cause and corrective actions for

this event have not been determined at this time, The cable resistance

issue in also reportable under 10CFR21.



END OF ABSTRACT



TEXT                                                          PAGE 2 OF 5



DESCRIPTION OF EVENT



On October 23, 1997, the plant was in Mode 4 (COLD SHUTDOWN) for the

sixth refueling outage (RF-6), and reactor [RCT] coolant temperature was

being maintained within a band of 100 to 120 degrees Fahrenheit (F) and

pressure was zero pounds per square inch (psi).  Engineers were

investigating degraded voltage margins and identified that at least five

electrical voltage calculations for the Alternating Current (AC) [ED] and

Direct Current (DC) [EJ] electrical distribution system design used

improper cable [CBL] resistance data provided by Sargent & Lundy (S&L) in

Table B of S&L Standard ESA-102, "Electrical Engineering Standard for

Electrical and Physical Characteristics or Class B Electrical Cables."

The standard established the Clinton Power Station (CPS) design basis

cable resistance used for determining cable tray [TY) loading and voltage

drop calculations.  Per S&L Power and Control Cable Specification

STD-EA-253, "General Specification for Power and Control Cable Insulated

with Ethylene-Propylene Rubber," CPS cables with voltage ratings below 5

Kilovolts (KV) have "tin-coated" copper conductors, however, Table B of

Standard ESA-102 provides resistance data for "uncoated" copper conductor

cables.  Coated cables have higher resistance values than uncoated cables

and yield slightly lower equipment terminal voltages than established in

at least five electrical calculations.  Condition report 1-97-10-414 was

written to Investigate and track the issue.  The Operations Shift

Supervisor (SS) entered additional restraints against restoring

operability for Technical Specification (TS) Limiting Condition for

Operation (LCO) 3.8.2, "AC Sources-Shutdown," and 3.8-10, "Distribution

Systems-Shutdown," as operability per these TS LCOs was already

restrained for other reasons.



On December 19, 1997, engineering determined that the Divisions 1 and 2

emergency diesel generator room vent fans [FAN], 1VD01CA and 1VD01CB,

could cause a loss of offsite power during a LOSS of Coolant Accident

(LOCA) block start coincident with a degraded voltage condition.  This

determination was based on increased cable resistance due to tin coated

conductors and higher than originally calculated fan brake horsepower.

The brake horsepower for these fan motors is based an a fan operating

temperature of 96 degrees F.  Analysis has identified that the fans are

required to operate at temperatures below 96 degrees F.  As air

temperature decreases more horsepower is required to drive the fans.  The

combination of increased brake horsepower and cable resistance could

cause the Divisions 1 and 2 emergency diesel generator room vent fans to

exceed a 13 second starting time under degraded voltage conditions.  CPS

degraded voltage analysis calculation 19-AQ-02, assumes that the 1VD01CA

and 1VD01CB fans accelerate to operating speed in less than 13 seconds.

Failure of the fans to start in 13 seconds could cause the offsite power

supply breakers [BKR] to trip on undervoltage due to transient loading

during a LOCA block start resulting in a lose of offsite power.

Considering the increased cable resistance due to tin-coated copper

conductors and increased brake horsepower due to colder air temperatures,

the assumptions of calculation 19-AQ-02 may not be valid.  Therefore, the

design of the Divisions 1 and 2 emergency diesel generator room vent

fans, 1VD01CA and 1VD01CB, in not in accordance with the design basis of

the plant.  The operability of Division 3 emergency diesel generator room

vent fan is not affected by this condition.



TEXT                                                          PAGE 3 OF 5



The tin coated copper conductors and increased brake horsepower

conditions for the Divisions 1 and 2 emergency diesel generator room vent

fans have existed since initial plant licensing on September 29, 1966.

At that time the plant was in Mode 5 (REFUELING) for initial fuel

loading, and reactor coolant temperature wag ambient and pressure was

atmospheric.



No automatic or manually initiated safety system responses were necessary

to place the plant in a safe and stable condition.  This event was not

affected by other inoperable equipment or components.



CAUSE OF EVENT



The cause for this event is still under investigation and will be

provided in a revision to title report.



IP expects to issue a revision to this report identifying the cause,

corrective actions, agreement of the safety consequences and

implications, and previous similar events by March 19, 1998.



CORRECTIVE ACTIONS



This corrective actions for this event have not been determined but will

be provided in a revision to this report.



ANALYSIS OF EVENT



This event is reportable under the provision of 10CFR50.73 (a) (2) (ii)

(B) due to the design of the 1VD01CA and 1VD01CB fan motors being outside

the design basis of the plant.



An assessment of the safety consequences and implications of this event

will be provided in a revision to this report.



ADDITIONAL INFORMATION



No equipment or components failed as a result of this event.



Previous similar event information regarding this event will be provided

in a revision to this report.



For further information regarding this event, contact A.  B.  Haumann,

Engineering Projects, at (217) 935-8881, extension 4078.



TEXT                                                          PAGE 4 OF 5



10CFR21 REPORT 21-97-051



On October 23, 1997, Engineers were investigating degraded voltage

margins and identified that at least five electrical voltage calculations

for the Alternating Current (AC), and Direct current (DC) electrical

distribution system design used improper cable resistance data provided

by Sargent & Lundy (S&L) In Table 2 of S&L Standard ESA-102, "Electrical

Engineering Standard for Electrical and Physical characteristics of Class

B Electrical Cables." The standard established the Clinton Power Station

design basis cable resistance used for determining cable tray loading and

voltage drop calculations.  Per S&L Power and Control Cable Specification

STD-EA-253, "General Specification for Power and Control Cable Insulated

with Ethylene-Propylene Rubber," CPS cables with voltage ratings below 5

Kilovolt (KV) have "tin-coated" copper conductors; however, Table B of

standard ESA-102 provides resistance data for "uncoated" copper conductor

cables.  Coated cables have higher resistance values than uncoated cables

and yield slightly lower equipment terminal voltages than established in

at least five electrical calculations.  Condition report (CR) 1-97-10-414

was written to investigate and track this issue.  IP determined that this

condition was potentially reportable under 10CFR, Part 21 on October 25,

1997.  IP has completed an revaluation of this issue and concludes that

it in reportable under the provisions of 10CFR, Part 21.



IP is providing the following information in accordance with

10CFR21.21(d)(4).  Initial notification of this matter will be provided

by facsimile of thin letter to the NRC Operations Center in accordance

with 10CFR21.21(d)(3) within 2 days of the data the responsible officer

approves this report.



(i)       Walter G.  MacFarland IV, Chief Nuclear Officer of Illinois

          Power Company, Clinton Power Station, highway 54, 6 miles East,

          Clinton, Illinois, 61727, is informing the NRC of a condition

          reportable under the provisions of reportable under the

          provisions of 10CFR21 by means of this report.



(ii)      The basic component involved in this report is the use of an

          incorrect design standard, S&L standard ESA-102, in the design

          of the cables installed at Clinton Power Station.



(iii)     The cable design using S&L standard ESA-102 was supplied to CPS

          by Sargent & Lundy.



(iv)      As discussed in the DESCRIPTION OF EVENT portion of this

          report, the nature of the defect is inaccurate cable resistance

          values supplied in S&L standard ESA-102 report for design of

          cables rated below 5 KV.  This information was used in

          electrical voltage calculations for the AC and DC electrical

          distribution systems.



          As discussed in the DESCRIPTION OF EVENT portion of this

          report, under degraded voltage conditions, the impact of

          increased cable resistance in conjunction with air temperatures

          below 96 degrees F an the Divisions 1 and 2 emergency diesel

          generator room vent fans could cause offsite power supply

          breakers to trip on low voltage during a LOCA block start.  A

          loss of offsite power reduces Clinton Power Station's defense

          in depth during a LOCA.



TEXT                                                          PAGE 5 OF 5



(v)       On October 23, 1997, Illinois Power identified that improper

          cable resistance values from data provided by Sargent & Lundy

          In Table B of S&L Standard ESA-102 wave used in at least five

          electrical voltage calculations for the AC and DC electrical

          distribution systems IP determined that this issue was

          potentially reportable under 10CFR, Part 21 on October 25,

          1997.



(vi)      The Improper cable resistance values were used to determine

          cable tray loading and voltage drop of cables rated for less

          than 5 KV at CPS.  Those applications have been evaluated and

          IP has concluded that this issue adversely affects the

          Divisions 1 and 2 emergency diesel generator room vent fans,

          1VD01CA and 1VD01CB, IP is not aware of other facilities that

          stay be affected by this issue.  The supplier of the improper

          cable assistance values (Sargent & Lundy) is aware of this

          issue.



(vii)     The corrective actions that IP will take for this event have

          not been determined but will be provided in a revision to this

          report.



(viii)    IP has no additional information to offer.



*** END OF DOCUMENT ***





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