IR 05000341/1993021

Insp Rept 50-341/93-21 on 931004-08.No Violations Noted. Major Areas Inspected:Compliance W/Sbo Rule 10CFR50.63

ML20059B078
Person / Time
Site:	Fermi
Issue date:	10/21/1993
From:	Gardner R, Westberg R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20059B076	List: IR 05000341/1993021 ML20059B073
References
50-341-93-21, NUDOCS 9310280025
Download: ML20059B078 (10)

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U.S. NUCLEAR REGULATORY COMMISSION 1 REGION Ill Report Number 50-341/93021 ' License No. NPF-43 Licensee: The Detroit' Edison Company

.1 6400 North Dixie Highway l Newport, MI 48166 l

Facility Name: Fermi 2 Nuclear Power Station i

i inspection At: Newport, Michigan

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Inspection-Conducted: October 4 through 8, 1993 Inspection Team: R. Westberg, Team Leader J. Neisler, Reactor Inspector D. Butler, Reactor Inspector S. Lee, NRC Intern A Pal, NRR ,

D. Shum, NRR l

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Approved By: bkM W ~ 10f 2. l]93 Rolf k-4/estber9 Date:

Approved By: O &

/0 f7 /ff 3 Ronald N. Gardner Date:

Inspection Summary:

Insoection on October 4 through 8. 1993 (Report No. 341/93021(DRS)).

. Areas Inspected:

Routine announced inspection of compliance with the SB0 rule,-

10 CFR 50.63, per Tl 2500/120, (SIMS Number MPA-A-22).

Results: No violations or deviations were identifie PDR E3

.G ADOCK 05000341 R:4 L. .

PDR 2

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DETAILS 1 1 .' Temporary Instruction (TI) 2500/120 (SIMS Number MPA-A-22) (Closed)

Concern about SB0 arose because of the accumulated experience regarding the reliability of AC power supplies. Many operating. plants have experienced a total loss of_offsite power, and more occurrences are expected in'the' futur i In almost every one of these loss of offsite power events, the onsite -

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emergency power supply has been available immediately to supply the power needed by vital safety equipment. However, in some instances, one of the redundant emergency AC power supplies has been unavailable. In_a few cases,

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there has been a complete loss of AC power. In addition, there have been "

numerous instances when emergency diesel generators (EDGs) have' failed to ,

start and run in response to tests conducted at operating plant !

The results of Unresolved Safety Issue, A-44, " Evaluation of Station Blackout Accidents at Nuclear Power Plants," indicated, that for one of the two plants evaluated, an SB0 event could be an important contributor to the. total risk from nuclear power plant accidents. Although this total risk was found to be small, the relative importance of SB0 events was established. This finding- '

and the accumulated diesel generator failure experience increased the concern '

about SB In a Commission proceeding addressing SBO, it was determined that the issue j should be analyzed to identify preventive or mitigative measures that can or should be taken. The purpose of this inspection was to verify the adequacy of plant programs, procedures, training, equipment and systems, and supporting documentation for implementing the SB0 Rule, 10 CFR S0.63 and to document the ;

results of this review in this inspection repor j Inspection Results Copina Duration Analysis

The SB0 Rule required that systems provide sufficient capacity and capabilit j to ensure that the core is cooled and appropriate containment integrity is '

maintained in the event of an SB0 for the specified duration. The specified i duration was calculated based on factors such as the offsite power design '

characteristics, emergency AC power supply configuration, and EDG reliability, i A minimum acceptable SB0 duration of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> was calculated for Fermi 2. The !

licensee provided the proposed four hour SB0 duration in a letter to the NRC dated April 17, 1989. The NRC reviewed the' proposed SB0 duration and agreed with the licensee's evaluation as documented in a NRC safety evaluation repor During the insr+ction, the team verified selected factors which were used to determine the SEO duration and reviewed plant documentation to verify that these characten stics were appropriate. The team also reviewed EDG reliability data'up to 199 The reliability value was 0.99 for the last-100-valid start and load run demands for DG No. 13, 0.98 for the last 50 demands for all EDGs, and 0.987S for the last 20 demands-for all EDGs. Based on a-

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review of the diesel reliability data, the team determined that the selection

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of a 0.'95 EDG reliability target value was appropriat .;

The team concluded that the 580 duration of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, that had been calculated in accordance with NUMARC 87-00, Revision 1, " Guidelines and Technical Bases for Numarc Initiatives," was acceptabl .2 Station Battery Capacity The team reviewed the station battery. capacity calculations to assure that

~ j battery capacity was adequate to power required SB0 loads for one hour. .The !

one hour duration was based on the availability of a one hour alternate.AC (ACC) power source to re-energize a battery charger for one division's SB0 i loads following an SB0 even The team verified that the battery sizing calculation included an appropriat aging factor of 1.25, and temperature correction factor of 1.11 (60 F ;

electrolyte temperature). However, the team found that the input current requirements for the constant KW loads (motors) were not properly adjusted for j voltage variations at the motor terminals during different load profile segments. In response, the licensee indicated that the margin available for 1 the constant resistance loads will compensate for the additional input current requirements for the constant KW load This appeared to be conservative to i the tea l The team determined that the battery terminal voltage profile calculation had ;

correctly consicered the aging factor and the temperature correction facto l However, the team's review identified the following minor errors 'n the l calculations: ' DC-5000 Vol I, Revision A, " Review of electrical motors for SB0"

• l An incorrect equation was used to calculate voltage drop for three !

phase AC motors (Vmcc - Rcab x 1.096(Temp. Factor) x Ilra). !

• There was no basis for the following criteria: "the required starting (inrush) current for a DC motor to start and accelerate i the load be greater than the full load running (FLA) current of the motor."

• A justification was required for the adequacy of low motor !

terminal voltages (for example, 50.6 volt for E41010C005 - HPCI Aux. Oil Pump) during startin DC-214 Vol 1, Revision B, *Short circuit calculation for DC system"

• The :able length (from MCC-2PA) a battery) used was 290 feet, I while the voltage drop calculatics used 120 feet and the pull len;.n was 120 fee ._ _ _

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' DC-4943 Vol. I, Revision E, "DC Equipment Operability"

• The amp-hour per plate calculation did not consider temperature and aging factors. For example, Attachment 9, Page 1, amp-hour per plate = (10/60) x (36.3/8) = 0.76 should be (10/6) x (36.3/8)

x (1.llx1.125/1.102) = 0.8 e There was no justification for the adequacy of low motor terminal voltages (for example, 50.2 volt for E4101C004) during startin ,

The licensee reviewed the above errors and provided an analysis which indicated that the overall conclusions of the calculations did not chang The team found this acceptable; however, the calculations should be revised to

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correct the errors. The team concluded that the battery capacity was adequate to power SB0 loads for a one hour duratio .3 Severe Weather procedure The team verified that the severe weather procedure provided adequate guidance to prepare the site for ensuing severe weather. The Fermi site has an severe weather characteristic of 1, as defined in Regulatory Guide 1.155, " Station Blackout." This characteristic is indicative of a location with a small l probability of having winds in excess of 125 miles per hour. Abnormal 1 Operating Procedure No. 20.000.01, Revision 16, " Acts of Nature," provides instructions for the identification and elimination of potential missiles from the site and operability verification of all required safety and emergency core cooling system {

l The team concluded that the severe weather procedure was consistent with the ;

guidance provided in NUMARC 87-0 .4 EDG Reliability Procram The team verified that the EDG reliability program target levels were consistent with the plant category and coping duration selected. Surveillance testing of the EDGs was performed in accordance with Technical Specifications (TSs) 4.8.1.1 and 4.8.1.2. The procedures monitor each start and load run of the EDGs and trend the reliability of the diesels. Failure rates are trended and trigger values are factored into the acceptance criteria. A management oversight program for reviewing reliability levels was being utilized and the program appeared to be functioning properl The team concluded that the EDG reliability program was detailed and was consistent with the guidance of RG 1.155. Section .5 *iternate AC (AAC) Power Source The team con:'uded that combustion turbine generator No. 11-1 (CTG-ll-1) had adequate capa:ity to power the 580 loads, had a reliability of greater tnan 0.95, and met all the requirements of NUMARC 87-00, Appendix .

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Fermi 2 committed to provide a one hour AAC power -source to SB0 loads by using the Appendix R dedicated CTG-ll-1. The team reviewed the ACC power source to virify that it met the criteria -specified in NUMARC 87-00, Appendix CTG-ll-1 is a 13.8kV,18,875kVA, 0.85pf self contained outdoor peaking generating unit with a diesel starting motor to provide black start '

capabilit In response to a concern raised by the team regarding the protection of the AAC system against likely weather related events, the 3 licensee indicated that the CTG-ll-1 unit and control compartments were

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designed as outdoor industrial equipment and that these structures have '

satisfactorily withstood all imposed wind and snow loads for approximately 25 years. The licensee stated that this should fulfill the uniform building code or the B0CA national building cod The team considered this acceptable, j v

The licensee demonstrated via special test procedure No. SOE 91-06, " Black l Start Test of CTG-ll-1," that CTG-ll-1 could energize the SB0 buses in 12 '

minutes and 59.2 seconds from the onset of SBO. A simulated SB0 scenario was performed on the Fermi 2 simulator on October 6,1993, using procedure N ;

20.300.01, " Loss of Offsite and Onsite Power," which recorded 37 minutes and 45 seconds from the onset of SB0 until the last required SB0 load was energized. The licensee indicated that recognition of an SB0 by the operator should occur in less than 30 seconds. The team considered the S80 start and load characteristics acceptabl NUMARC 87-00 requires the AAC power source to be started and brought to i operating conditions that are consistent with its function as an AAC source.at '

intervals not greater than 3-months, following manufacturer's recommendations-or in accordance with plant developed procedures and once every refueling outage. It also requires a timed start and rated load capacity test. The -t team noted that the plant's TS require CTG-ll-1 to be tested monthly. and once ,

per 18 months during refueling. Both the monthly and 18 month test start-loaded CTG-11-1 to greater than 10MW and verified synchronization to the grid in s 15 minutes. The team considered CTG testing acceptabl The team noted that the licensee did not perform a voltage drop calculation of the SB0 loads when fed from CTG-ll-1. A preliminary hand calculation was ,

performed to verify that adequate voltage will be available to the SB0 buse The team concurred that the SB0 loads would have adequate voltage since CTG-ll-1 feeds through a step down transformer with an on-load tap change The licensee committed to perform a formal voltage analysi . Instrumentation Preventive Maintenance The team noted that 16 CTG-11-1 protective relays had not been calibrated since 1987. In response, the licensee provided the team an August 12, 1993 letter, " Relay Periodic Test Intervals," which documented a planned increase of peaker relay calibration intervals from 5 to 7 years. This was based'on past periodic maintenance reviews and the Relay System Performance group trending program which monitors relay performance. In addition. CTG-ll-1 has a 95% start-load reliability with no failures attributed to the protective relay . - .

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The CTG-11-1 relays were subsequently calibrated and the data reviewed by the

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team with acceptable result !

2. CTG-ll-1 Preventive Maintenance The team reviewed the CTG preventive maintenance program including work

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planning and review, corrective action process, root cause analysis, i procurement, spare part availability, functional testing, maintenance and personnel qualifications. The team concluded that the licensee had implemented an adequate CTG preventive. maintenance progra .6 Compressed air systems l

The team verified by review of plant drawings and operating procedures that !

the plant does not rely on air operated equipment during the first hour of an !

SB0 event. The team also confirmed that nitrogen would be available to !

operate the low-low setpoint relief valves and the automatic depressurization system safety relief valves (SRVs) as required to cope with an SB0 duration of four hours and that adequate backup sources were availabl Fermi 2 has 2 compressed air . systems, the station compressed air system and a safety related instrument air system powered by a class 1E electrical power I source. Both systems are lost during an SB0; however, instrument air is available within one hour since it can be repowered by the AC The SRVs of the automatic depressurization system and the low-low setpoint- (

relief valves use a pressurized nitrogen supply for operation. Each valve has an accumulator sized to provide 5 actuations of the valve upon loss of nitrogen supply or containment isolation. The isolation valves are DC powered and can be reopened to recharge the accumulators. In addition, the accumulators can be repressurized from the instrument air system or an >

emergency nitrogen hook up outside .of the reactor building. The accumulators, pressure controllers and valves were included in the plant preventive

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maintenance progra The team concluded that there was reasonable assurance that air or nitrogen i would be available to perform required SRV operation during' an SB0 and that no' !

SB0 functions were dependant on compressed ai .7 Containment isolation The team verified that the licensee had correctly identified the containment isolation valves which cannot be justified as necessary for coolant inventory ,

control or that do not conform with the guidance described in NUMARC 87-00 for exclusion from consideration as isolation valves of concern. Thirteen containment isolation valves required manual closure and or position verification locally during an SB0 event. The valves were locate: so'as to be l accessible to operators under SB0 condition '

The thirteen vahes were identified in the SB0 procedure and the procedures were included in the training program. In addition, the operators are

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.' required to verify that containment isolation, when it is required, has been  !

succesisfully accomplishe '2.8- Condensate Storage Canacity The team verified that Fermi 2 had adequate condensate storage capacity to cope with an SB0 for the specified duratio o

- The condensate inventory calculation results indicated that 126,480 gallons of condensate are required to remove decay heat and to cool down the: reactor

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coolant system during a four hour SB0' event. The TSs. require a minimum of a-150,000 gallons to be maintained-in the condensate storage tank which exceeds '

.the guidance provided in NUMARC 87-00, Section 7. ,

Alternate water sources were available, if required, from the suppression pool i or core spray storage tank. Procedures were available to line up RCIC and HPCI to these alternate sources. The team reviewed these procedures and found 3 them acceptabl ' RCIC and HPCI Systems

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The team verified by reviewing drawings and discussions with cognizant licensee engineering and operations personnel that valves within the HPCI and -

RCIC systems could be operated independent of the plant normal AC power '

systems. The valves that could prevent each system from performing its

-function were two or more motor operated valves in series. One AC powered valve was normally open and would remain open on loss of AC power. The other  ;

MOV was DC powered and independent of the AC systems, enabling the operator tt  !

use either RCIC or HPCI during an SB '

i The valves from the alternate water source to the pump suctions were D l powered remote-manual MOVs. The ADS valves were operated by pressurized i nitrogen with DC powered control systems. All of these valves were included in the plant preventive maintenance progra :

The team concluded that RCIC and HPCI valves could perform their required J functions independent of the AC power system '

2.10 Heat Tracina/ Freeze Protection ~i The team reviewed the licensee's freeze protection procedure to determine '!

whether equipment that relies upon heat tracing was cdequately protected when  ;

class lE AC power was not availabl !

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External water sources were protected within insulated tanks. Critical pipinc-  ;

was located underground below the frost line and valve pits are heated by electric space heaters. No heat tracing was required for these systems durir.;  ;

a four hour SB0 event. Based on discussions with cognizant licentee  ;

personnel, review of applicable drawings and procedures and walk through of '

plant' areas, the team concluded that water systems would be adequately protected from freezing during a postulated S80 even :l l

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The team verified by area walkdowns and review of heat-up calculations for. the dominant areas of concern (DAC) that there was reasonable assurance that the equipment located within the DACs would remain ' operable for the duration of an SB0 even Heat generation calculations for various equipment, piping and components for-

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the areas containing equipment required to cope with an SB0 event-were '

performed in accordance with NUMARC 87-00 guidance. Heat' generation ratios from the guide were used to determine area peak temperature. Except for the control room-and drywell, the NUMARC 87-00 steady state method was:used to determine the peak temperature during a four hour SB0 event. Calculated peak, temperatures were less than the limits prescribed in NUMARC 87.-00'for -

equipment operability. The main steam tunnel calculated peak temperature '

exceeded the NUMARC 87-00 guidance; however, review of equipment qualification (EQ) documentation indicated that the peak terperature was less than the EQ-limi The transient heat transfer calculation method was used to analyze the transient temperatures in the control room and drywell. for the first hour of

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the four hour SB0 event. Since power from the AAC would be available to provide cooling to these areas in one hour, extending the temperature calculations to four hours was not necessar .

The team concluded that calculations to identify the DACs were technically >

sound and that SB0 equipment in these areas were environmentally qualified to remain operable during an SB0 even .12 Emeroency liahtina and Communications

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The team verified through walkdowns of equipment required to mitigate the ~

consequences of an SB0 that emergency lighting and communications were-available for use by the plant staf .13 Procedures and Proarams The team verified through the review of SB0 procedures, QA audit and surveillance reports, observation of a simulated SB0 scenario, walkdowns of-various SB0 equipment, and interviews with operators and trainers that.SB0 procedures had been adequately developed and implemented and that the operators were sufficiently trained to respond to an S8 During observation of the simulator SB0 scenario, the team noted a labeling error in Abnormal Operating Procedure No. 20.300.01, " Loss of Offsite and Onsite Power." The main control room labels for the 24 Volt Battery Charger #

Switches were Al CONT. and A2 CONT., where the procedure indicated 21A-1 and 21A-2, respectively. The licensee immediately corrected these procedure errors. Aside from these labeling errors, the team concluded that the 580 procedures provided sufficient information to the operators and fulfilled SER commitments to open cabinet and room doors, and to disable Reactor Core RCIC and HPCI room area high temperature isolation signal _-

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The team also verified. and concluded'that the procedures for restoring offsite l power and EDG power to the safe shutdown buses,. containment isolation '

verification, limiting reactor coolant inventory' loss, reactor scram

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verification, RCIC or HPCI initiation, and battery capacity monitoring were adequately developed and implemente Annual SBO.in-class procedure training for licensed and non-licensed operator 'i were completed. The licensed operators received additional. SB0 simulator i training. The team considered training walkdowns of SB0 equipment external to ~

the main control room by non-licensed operators as good training practic However, the team noted that these equipment walkdowns were not conducted during the most recent.SB0 trainin ,

The team reviewed the licensee QA audits, surveillances, and quality inspections and concluded that SB0 structures,; systems, and components were adequately inspected. In addition, the licensee's SB0 management' policy was :

adequately controlling the design, procurement,. and documentation. process, t Surveillance, calibration and operational procedures adequately described-inspections, tests, administrative controls, and training necessary for compliance with 10'CFR 50.6 The DER process adequately controlled items that did not conform to specified' requirements by ensuring failures, malfunctions, deficiencies, deviations ~ defective -components, and

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nonconformances were promptly identified, reported, and co- ecte ,0 Exit interview  ;

The team met witr licensee representatives (denoted in Appendix A) on October ,

8, 1993, and sum arized the purpose, scope, and findings of the inspectio !

The team discussed;the likely informational content of the inspection report ;

with regard to documents or processes reviewed by-the team-during the ;

inspection. The licensee did not identify any such-documents or processes as '

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Appendix A l

Persons Contacted Detroit Edison Company

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D. Gipson, Senior V.P., Nuclear Generator '

R. Stafford, Manager, Nuclear' Assurance R. McKeon, Plant Manager W. Miller, Jr., Director, Nuclear Licensing _,

T..Schehr, Supervisor Planning, Work C'ontrol  ;

L. Collins, Supervisor-Electrical, Plant Engineer ,

D. Ockerman, D.N.T., J. Pendergast, Compliance Engineer, Licensing R. Szkotnicki, Supervisor - Inspection & Surveillance, Quality Assurance i P. Fulton, Supervisor, Electrical Systems Engineer, Technical Systems Eng

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R. Gummaraju, Lead Auditor, QA T. Bradish, QA Audits Supervisor, NQA A. Kowalczuk, Director, PH Support, Nuclear Assurance J. Deflbaugh, Senior Engineer, Plant Engineering M. Hobbs, Senior Engineer, Technical Engineering ,

J. Malaric, Supervisor Mods, Technical R. Eberhardt, Supt Rad Protection, Rad Protection J. Tibai, Principal Compliance Engineer, Licensing J. Plona, Supt Operations, Operations W. Tucker, Supt Technical, Technical L. Fron, Supt Technical J. Molloth, Maintenance Superintendent, Maintenance J. Koste, Director, Nuclear Security J. Nyquist, Supervisor, Safety Engineer .

G. Goodman, SNTS, Nuclear Training J. Walker, General Director, PE 3 J

R. Haupt, Principal Engineer, Plant Engineering - I&C J. Green, Supervisor, Plant Engineering, I&C 4 J. Flint, Acting Supervisor, OPS Support, Operations )

i U. S. Nuclear Requlatory Commission l

l W. Kropp, Senior Resident inspector, NRC l K. Riemer, Resident inspector, NRC ]

T. Colburn, Project Manager, NRR i R. Gardner, Chief Plant Systems Section l

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