IR 05000315/1993022
| ML17331B086 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 11/23/1993 |
| From: | Falevits Z, Gardner R, Mendez R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML17331B085 | List: |
| References | |
| 50-315-93-22, 50-316-93-22, NUDOCS 9312030192 | |
| Download: ML17331B086 (7) | |
Text
U.
S.
NUCLEAR REGULATORY COMMISSION
REGION III
Reports No. 50-315/93022(DRS);
No. 50-316/93022(DRS)
Docket Nos.
50-315; 50-316 Licenses No.
DPR-58; No.
DPR-74 Licensee:
Indiana Michigan Power Company 1 Riverside Plaza Columbus, OH 43216 Facility Name:
D.
C.
Cook Nuclear Power Plant Units 1 and
Inspection At:
AEP Offices - Columbus, OH Inspection Conducted:
November 1 - 5, 1993 Inspectors:
a evits
//-z3-g
.
Men ez
/I- >.3
- "-g bate Approved By:
~
~
R.
N. Gar ner, C ie Plant Systems Section Ins ection Summar ri I~.~ I~3 bate No. 50-316 93022 DRS Areas Ins ected:
Announced followup inspection of previously identified EDSFI findings in accordance with Temporary Instruction (TI) 2515/111.
Results:
The inspection determined that the licensee made adequate progress in resolving EDSFI. issues.
Seven previously identified findings were closed, and three remained open (Section 2.0).
9312030192 931123 PDR ADOCK 05000315 Q
, DETAILS 1.0 Princi al Persons Contacted Indiana Michi an Power Com an
- W. Smith, Chief Nuclear Engineering
- S. Steinhart, Manager, Nuclear Engineering Electrical Division, NPED
- J. Jeffrey, Manager, Power Systems and Human Factors (PS&HF)
- J. Anderson, Assistant Manager, Power Systems and Human Factors (PS&HF)
- M. Finissi, Electrical Engineer
- M. Ackerman, Nuclear Licensing, Inspection Coordinator
- D. Malin, Section Manager, Nuclear Licensing
- M. Stark, Systems Engineer Section Head
- S. Brewer, Group Manager, Nuclear Safety Licensing
& Assessment (NSL&A)
- Denotes those present during the exit meeting on November 5,
1993.
2.0 Action on Previousl Identified Ins ection Findin s
0 en 0 en Item 315 92003-01 DRS 316 92003-01 DRS
The EDSFI team identified concerns with (1) pre-fault'voltages used in old calculations, (2)
600V and 4kV switchgear interrupting capabilities, and (3)
4kV switchgear momentary short circuit ratings.
The licensee performed short circuit calculation No.
PS-4KVD-002,
"A Fault Stand Circuit Calculations,"
dated October 29, 1993, and concluded that the 600V and the 4kV switchgear were capable of interrupting calculated asymmetrical fault currents.
In addition, the licensee determined that a three-phase bolted fault at the motor terminal was within the switchgear ratings.
However, the momentary duty ratings of 4kV switchgear would, in some cases, be exceeded by up to 20.6N for a fault at the load side of the circuit breaker.
Pending further licensee evaluation and NRC review, this item will remain open.
b.
Closed Unresolved Item 315 92003-02 DRS '16 92003-02 DRS
The EDSFI team's review of preliminary 1CD EDG loading calculation, indicated that there was only.a 30 kW margin at the emergency diesel generator (EDG) continuous rating of 3500kW.
The team also had concerns that the licensee failed to consider unsubstantiated loading conditions of the other three EDGs, unaccounted cable losses, and possible manual reconnection of loads.
As a result of the team's concerns, the licensee developed load flow calculations for each EDG.
The load flow calculations considered three different postulated design basis events (DBEs) which could occur coincident with loss of offsite power (LOOP).
All the loads automatically connected and cable losses were tabulated in the load studies.
The emergency operating procedures (EOPs)
provided a warning not to exceed the 3500kW rating of the EDGs during manual loading.
The inspectors verified that real, reactive and total power requirements
were within the continuous rating of each EOG, including the 1CD EDG, and that licensee's methodology and assumptions were conservative.
This item is considered closed.
Closed 0 en Item 315 92003-03 ORS 316 92003-03 ORS
The EOSFI team identified that the insulation" rating of. 600V equipment (including cable's and circuit breakers)
was inadequate for the system:operating voltages.
The team determined that the maximum cable insulation and air circuit breaker voltage rating was 600V a'5X, while the operating voltage could be as high as 600V a 10X.
In response to the team's concern, the licensee rev'ised the EDG loading procedure 1 (2)
THP 4030 STP.217A.
The revised procedure required that bus voltage shall not exceed 630V on the 600V bus.
This item is considered closed.
0 en Unresolved Item 315 92003-04 ORS
.
316 92003-04 DRS The EDSFI team identified the following four concerns:
(1) the bus voltage, could decrease to a value just -above 79X for a period of 2 minutes.
Safety system operation at this voltage level was not examined and no objective'vidence could be found for justification of the 2 minute time delay; (2) there was no formalized check of the ability to start 600V motors at the degraded grid setpoint; (3) relay setting and calibration errors were not considered; (4) the worst case 4kV bus voltage postulated for 1992 could drop below the degraded grid setpoint.
To resolve concern (2) the licensee performed, checked and-formalized the calculation that successfully demonstrated the ability of the 600 V motors to start at the degraded grid setpoint.
The inspectors reviewed the calculation and found it acceptable.
To resolve concern (3) the licensee performed calculation PS-4KVP-012,
"Undervoltage Equipment Tolerance,"
dated February 6,
1-993.
When the relay setting and calibration errors were considered, they were found to be within the established tolerance for degraded grid voltage.
For concern (4) the licensee changed the 4kV and 480 transformers no load tap settings to avoid the possibil.ity of lower bus voltages on auxiliary systems.
The inspectors
.reviewed the licensee's corrective actions for concerns (2), (3)
and (4) above and found the actions acceptable.
The inspectors considered item (1) open pending evaluation of this issue by ERR.
Closed Unresolved Item 315 92003-05 ORS '16 92003-05 ORS
The EDSFI team identified that the battery short circuit calculations were based on normal operating conditions for the dc -system and did not consider the worst case temperature and voltage conditions.
The inspectors considered this concern resolved based on IEEE STO 946-1992, Section 7.9. 1, which states,
"tests have shown that an increase-in electrolyte temperature (above 25'C) or elevated battery terminal
voltage (above nominal voltage) will have no appreciable effect on the magnitude of short-circuit current delivered by a battery."
This item is considered closed.
0 en Unresolved Item 315 92003-06 ORS 316 92003-06 DRS
The EDSFI team noted that 250Vac fuses were used in all 250Vdc circuits ranging from 10A to 600A.
A licensee report that analyzed this issue did not look at worst case conditions.
Review of this issue by the inspectors indicated that there was insufficient engineering or test data to assure that the 250Vac fuses would adequately protect 250Vdc circuits.
Pending licensee review, consideration of fuse testing and further NRC review, this item remains ope'.
Closed 0 en Item 315 92003-07 ORS 316 92003-07 DR:
The licensee did not have voltage 'drop calculations for the 120Vac circuits which were fed from the engineered safety system (ESS) inverters.
In response to the EOSFI team's concern, the licensee developed calculation PS-CRIO-004.
Based on their review of the calculation, the inspectors concluded that the safety-related 120 Vac circuits fed from the ESS inverters,should receive adequate voltage at the terminals.
This item is considered closed.
Closed 0 en Item 315 92003-08 DRS 316 92003-08 DRS
The licensee's seismic analysis of the 60,000 gallon diesel fuel oil store==
tank did not consider the motion of the oil during DBE and OBE events.
The inspectors reviewed licensee's calculation DC-D-3050-308-SC,
"Diesel Generator Fuel Oil Tank," dated Harch 13, 1992.
The calculation determined that the magnitude of the sloshing forces were less than the magnitude of the active earth pressures.
Since the internal sloshing forces oppose the external active soil pressure the motion of the fuel oil inside the tank does not cause
"
the net stresse's in the tank to increase.
The inspectors concurred with this analysis.
This item is considered closed.
Closed 0 en Item 315 92003-09 ORS 316 92003-09 ORS
The EDSFI team noted that there was no seismic analysi,s of the buried portion of the diesel fuel oil piping and the tank level/alarm bubbler instrument air tubing.
The licensee performed calculation DC-0-12-FO-2342 dated June 15, 1992.
which concluded that the components were adequate for seismic OBA and OBE conditions.
The inspectors reviewed'he calculation and concurred with the licensee's conclusions This item is considered close "
J Closed 0 en Item 315 92003-10 DRS
.
316 92003-10 ORS
The EOSFI team observed that there was approximately-a four foot gap between the inlet and the supplementary panel ventilation ducts inside the 2CD EDG-room.
The team was concerned that the temperature inside the EOG
.
control panels could exceed the design limit of 104'F.
, Subsequently, the licensee completed temperature surveys and found that under worst case conditions, the temperature inside the panels could reach 116'F.
However, the licensee, using NUHARC guidelines, concluded that the electronic components in the panels exposed to a temperature of 116'F would operate reliably.
The licensee planned to move the ventilation ducts and issue modification 2-HH-426 to initiate work activities by the end of 1993.
Based on this commitment, this item is considered closed.
3.0 Review of Licensee EDSFI Commitments The inspectors verified licensee actions to address the various commitments made in the EDSFI report.
The licensee has completed actions on most of the commitments and commenced actions on the remaining open commitments.
For example, the licensee has initiated a Calculation Upgrade Program which will identify and review existing electrical calculations required to support design basis of the electrical distribution system.
About 60% of the calculations are complete; full completion is scheduled for Harch 15, 1995.
The inspectors had no further concerns with the licensee's implementation of the commitments.
The corporate electrical engineers that interfaced with the inspectors were cooperative and very knowledgeable in their area of expertise.
4.0 Exit Interview The inspectors conducted an exit meeting on November 5,
1993, to discuss the major areas reviewed during the inspection and the inspection findings.
Licensee representatives who attended this meeting are listed in Section 1.0 of this report.
The licensee did not identify any document or processes as proprietary.