IR 05000321/1993019
| ML20059K634 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 10/26/1993 |
| From: | Fillion P, Shymlock M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20059K632 | List: |
| References | |
| 50-321-93-19, 50-366-93-19, NUDOCS 9311160133 | |
| Download: ML20059K634 (7) | |
Text
-
-
,
,
.
od UHfTED STATES e\\
NUCLEAR REGULATORY COMMISSION j
~.
g .
'
2S REGloN 11 1$
Q.
101 MARIETT A STREET, N.W., SUITE 2900 7,
y ATLANTA, GEORGIA 30323-0199
%
e
"% * *,. /
e Report Nos.: 50-321/93-19 and 50-366/93-19 Licensee: Georgia Power Company P. O. Box 1295 R
j Birmingham, AL 35201 Docket Nos.:
50-321 and 50-366 License Nos.: DPR-57 and NPF-5 q
!
Facility Name: Hatch 1 and 2 Inspection Conducted: October 4-8, 1993 i
Inspector:
f.
/a/2/[9]
j P.FillionG
'
/
l Date Signed
Approved by:
d 1P1
/0 46-93 H.ShymlockVChief Date Signed Plant Systems Section Engineering Branch Division of Reactor Safety
!
SUMMARY Scope:
This special, announced inspection was conducted to assess the adequacy of the licensee's corrective actions for safety-significant findings identified during the Electrical Distribution 5ystem Functional Inspection (EDSFI) documented in NRC Deport 321, 366/91-202.
Results:
In the areas inspected, violations or deviations were not identified.
The licensee's effort to address the EDSFI findings was adequate. Two Inspector Followup Items were identified during assessment of the corrective actions. One involves providing better operator guidance for manual diesel loading (paragraph 2.3) and ti,e other involves the probable need for additional coordination studies (paragraph 2.5).
Violatioin 91-202 which was in the area of design control remains open because the licensee's response is under review by the NRC (paragraph 2.1).
\\
9311160133 931102I PDR ADOCK 05000321 G
- .
.
.
.
.
REPORT DETAILS 1.
Persons Contacted Licensee Employees
- J. Branum, Project Engineer, Corporate Licensing B. Mosley, Operations Engineer-
- J. Payne, Senior Engineer, Nuclear Safety and Compliance
- D. Read, Assistant Site Manager for Plant Support
- K. Robuck, Superintendent, Plant Modifications and Maintenance
- S. Tipps, Manager, Nuclear Safety and Compliance
- P. Wells, Operations Manager Other licensee employees contacted during this inspection included engineers, technicians, and administrative personnel.
Other NRC Employees:
- G. Wiseman, Reactor Inspector
- L. Wert, Senior Resident Inspector
- Attended exit meeting 2.
Electrical Distribution System functional Inspection followup (2515/111)
The inspection assessed the adequacy of the licensee's carrective actions for findings and violation identified during the EDSFI-conducted June 10 through July 12, 1991 (NRC Report 321,366/91-107.). These findings and the licensee's corrective actions are addressed in the-following paragraphs.
2.1 (0 pen) Violation 91-202, Design Control four deficiencies identified in the EDSFI report issued by NRC Headquarters were examples of a violation issued by NRC Region II Office on October 7, 1991. The licensee's response to the Notice of Violation agreed that three of the examples cited were valid. The response stated that one of the examples did not constitute a violation. The example being denied by the licensee (Deficiency 91-202-01)- involves the fact that Hatch does not have installed degraded grid protection relays meeting the requirements of the Generic Letter titled ' Degraded-Protection for Class IE Pouer Systems," dated June 2, 1977.- The basis for the denial is under review by the NRC. The licensee has responded to a request for information and meetings were held to clarify the issue.
Corrective actions for the remaining three deficiencies as stated in the response to the Notice of Violation were addressed as follow.
.
,
i
~
(Closed) 91-202-02, load Increase and Change of SAT ID Tap. The essential concern of this deficiency is that the tap setting (or transformer ratio) for the ID startup auxiliary transformer was changed from 100 percent to 102.5 percent in 1987 and that a formal 10CFR50.59 review had not been performed. The corrective action for this problem
was to include the transformer tap settings on official plant drawings.
According to the licensee's program this would ensure that any change to a tap setting would be treated as a plant modification, and receive the i
proper reviews. 130 inspector reviewed Drawing No. A-43738 rev. 007,
" Power Transformer Data and Tap Settings", and verified that the corrective action had been implemented. Therefore, this item is closed.
(Closed) 91-202-06, Incorrect Coordination of the EDG Circuit Breakers.
The EDSFI team had found that the overcurrent protection for the diesel generator did not coordinate with overcurrent protection for the individual feeder breakers on the 4160 V bus. This could have resulted in the generator breaker tripping for a fault on a motor feeder rather than the motor feeder breaker.
To correct this situation, the licensee made an adjustment to the voltage restrained overcurrent relays (IJCV51)
at each generator. As stated in the EDSFI report,91-202, the change was made during the inspection.
This item is closed.
(Closed) 91-202-07, Coordination of 120 VAC and 125 VDC Circuits.
Calculation No. 87 rev. 3, by Bechtel Corporation was an overcurrent protective device coordination study. It contained a list of
%cceptable" breaker / fuse combinations that would coordinate. The EDSFI-l team identified some combinations on the list that actually did not coordinate.
No actual uses of these problem combinations were identified by the team, but since they were on the " approved" list the j
concern was that they could be used in the future. The corrective action for this problem was that Calculation No. 87 was revised to state the proper scope and purpose of that calculation. Also, the distribution system was reviewed for any possible mis-coordinations.
'
This review identified eleven problem cases. The inspector confirmed that Calculation No. 87 was revised as stated. The inspector reviewed Design Change Request No. 2H92-097, rev 0, dated May 6, 1992, to change seven fuses at Unit 2.
The inspector reviewed Design Change Requast No.
lH92-096, rev. O, dated May 6, 1992, to change four fuses at Unit 1.
The inspector also reviewed the approved Unit 1 and Unit 21994 outage design change implementation lists to confirm that these design changes were included. The inspector also confirmed that the new fuses would correct the coordination problem. This item is closed.
>
In summary, the violation remains open because the licensee's response to part one of the violation is under review by the NRC.
2.2 (Closed) Deficiency 91-202-03, Fast Transfer Permissive Relay. The EDSFI team reviewed the design and surveillance associated with the various undervoltage protection relays, and identified the need for a revision to Technical Specifications Tables 3.2-13 and 4.2-13 to make
,
the Technical Specification consistent with the as-built design with regard to the startup transformer 1C undervoltage relays. The inspector l
,
^
.
.
.
,
.
reviewed Georgia Power Co. letter HL-1825 from J.T. Beckham, Jr. to NRC dated November 18, 1991, requesting Technical Specification change to delete tables on the undervoltage relays.
The inspector also reviewed
,
NRC letter from K.N. Jabbour to J.D. Woodard of Georgia' Power Co. dated June 24, 1993, approving the change request under Amendment No. 186 and stating it resolves this open item. The inspector also reviewed the i
licensee's copy of the Technical Specification and confirmed the revised pages were inserted. This item is closed.
2.3 (Clcsed) Deficiency 91-202-04, EDG Remote Shutdown Procedure. The guidance in the remote shutdown procedure was inadequate in that it i
could have resulted in overloading the diesel generator during manual loading operations. During this inspection (93-19) the inspector
'
reviewed Request for Engineering Assistance No.'s90-722 and 91-786-i which are reports prepared by Bechtel Power Corp. of Gaithersburg, MD, transmitted to Hatch on December 23, 1991.
The reports contain the
'
calculation of new diesel generator pre-load power (or current) values.
>
Operations Procedure 31RS-0PS-001-1S, " Shutdown from Outside Control Room", rev.1, effective April 9,1992, incorporated the new pre-load.
values and provided proper guidance to the operator for starting the
'
residual heat removal and residual heat removal service water pumps.
The new procedure also gave correct values for the diesel generator
. f continuous rating and the seven-day rating in amperes. The inspector agreed that the new pre-load values were correct and that the revised
procedure corrected the original problem identified by the EDSF1 team.
j However, the inspector identified a problem with the diesel generator i
operating procedure. The number and title of that procedure was:
3450-R43-001-IS, rev. 14, " Diesel Generator Standby AC System".
The
,
problem may be stated as follows. The 31RS procedure states on page 27:
-
" Refer to 3450-R43-001-lS to reduce diesel loads if required." However the 34S0 procedure does not contain any such guidance. The inspector expressed concern that this situation could confuse an operator and cause him or her to loose time in carrying out the remote shutdown procedure. The licensee agreed that the 3450 procedure should be revised to provide guidance in reducing load should that be necessary to
,
allow starting a large load such as the residual heat removal pump.
,
In ammary, the original problem was corrected, and that item is closed.
A new problem was identified therefore a new open item is established, Inspector Followup Item 93-19 01, Operator Guidance for Loading Diesel Generator.
'
2.4 (Closed) Unresolved Item 91-202-05, Sizing of 250 VDC/600 VAC Inverters.
The EDSFI team questioned the capacity of the inverters which supply power to certain key valves in the Residual Heat Removal, Reactor Core Isolation Cooling and Reactor Recirculation Systems. Several of the
valves could operate simultaneously.
The question was whether the
.
valves could operate simultaneously and still meet the stroke time l
requirements given in the Inservice Inspection Plan. To address this unresolved item the licensee performed a test to demonstrate the l
'
inverter's capacity. Test Procedure 345V-R44-001-IS, "LPCI Inverters I
.
'
.
.
'
.
-
,
,
l-~
operated simultaneously. Results of this test are given in the table Load Testing", was enhanced to measure stroke time when the valves were l
below.
'
Valve Number Valve Function 3troke time Measured Direction
!
Criteria Time of Travel-Ell-FISA RHR injection s 26 s 23.8 s Open Ell-FISB RHR injection s 26 s 23.1 s Open E11-F07A RHR min flow s 24 s 20.1 s Open Ell-F078 RHR min flow s 24 s 21.5 s Open E51-F07 RCIC steam supply s 20 s 14.6 s Close B31-F31A Recirc disch s 33 s 27.6 s Close B31-F31B Recirc disch s 33 s 28.7 s Close The inspector evaluated these results, reviewed the system operation and the Inservice Testing Plan, and concluded that the test demonstrated that the inverters have sufficient capacity. This item is closed.
2.5 (Closed) Observation 91-202-08, Discrepancies in Coordination Calculations. The essential concerns expressed in this observation were:
The overcurrent protective device coordination and prctection studies were fragmented into separate individual studies.
The various coordination / protection studies were not done using a
standard format which clearly stated all the design inputs.
The time vs current characteristic of a particular relay with a
given setting was represented differently in different portions of the study.
A conclusion of one coordination study, namely that the
instantaneous element of 600 V feeder breakers not be set higher than 2400 A, may not have been applied in other coordination studies.
The licensee has three separate coordination / protection studies. One study which was done by Georgia Power Co. covers the high-voltage and medium-voltage portions of the distribution system. This study includes the main breakers to the 600 V switchgear because those breakers utilize relays for protection similar to the higher voltage level e
.
,
-
-
,
A second study is 'part of the safe shutdown 10CFR50 Appendix R analysis.
This study was limited to Appendix R requirements. At one point, a
'
modification was implemented to upgrade a number of trip devices at 600
V switchgear. A coordination study was done to support this-(
'
modification. This third study was made to ensure that the Appendix R
'
analysis was not invaliaated by the modification, but the Appendix R
'
coordination study was not revised.
The inspector concluded that, while the overall coordination / protection study comprises three separate studies, no excessive fragmentation
'
exists that would by itself cause errors in any existing or future
'
study. The inspecNr also concluded that since the EDSFI team did not l
identify any specific coordination problems that the licensee is not
'
required to re-work the studies solely for the purpose of enhancing the format.
With regard to the guideline calling for a maximum setting of 2400 A at 600 V switchgear, the inspector ascertained the following:
The guideline was established by those persons performing the high/ medium-voltage study as a setting that would-guarantee coordination at all buses. The inspector reviewed the trip device setting sheets for the safety-related 600 V switchgear, and identified that twe breakers were set above 2400 A.
These breakers were analyzed further and found
,
to coordinate with upstream breakers, and therefore the settings were acceptable.
-
The foregoing facts and conclusions resolve three of the four concerns stated in Observation 91-202-08.
There are gaps in the coordination / protection study of the low-voltage
,
system.
Since the study only covers the Appendix R requirements, non-
Appendix R related portions of the system and non-Appendix R considerations are not covered. The licensee stated that a report being
prepared in response to the EDSFI observation in this area will probably reach the same or similar conclusions when it is completed. The licensee did not disagree with the inspector's conclusion that additional coordination / protection studies would probably have to be done to ensure that the system has proper coordination and protection
throughout.
In fact, they stated that some coordination problems have been identified in the non-Appendix R portion of the DC Distribution
System. These occur between power breakers having long-time and instantaneous type trip devices and molded-case breakers at motor i
control centers.
Furthermore, the fourth concern stated in the EDSFI observation, ie, discrepancies in the time vs current characteristics of relays, was not specifically addressed by the inspector during this
inspection.
For the reasons stated above the NRC intends to perform
'
further inspection of the licensee's coordination / protection studies.
Therefore, Inspector Followup Item 93-19-02, Potential Electrical Coordination Problems, is established. Observation 91-202-08 is' closed.
2.6 (Closed) Deficiency 91-202-09, Discrepancies in Mechanical Design Documentation.
The EDSFI team identified five discrepancies in the
,
documentation they reviewed related to mechanical systems.
The licensee j
has since corrected each of these discrepancies, and the inspector
.
,
,
i
l
.
-
.
.
confirmed that they have been resolved. This item'is closed.
i 2.7 (Closed) Deficiency 91-202-10, Plant Service Water System. The EDSFI team identified the potential for overpressurizing the portion of Plant t
Service Water System piping that serves the IB emergency diesel generator.
It was postulated that the section of piping could become overpressurized upon shutdown of the diesel and isolation of the piping because residual heat in the heat exchanger could cause heatup of the water. To address this concern, the licensee monitored the service water pressure at panel 1Hil-P652 on gauge IP41-R613 after a diesel
generator surveillance run when valve IP41-F340 was closed.
It was observed that pressure in the section rose to Plant Service Water System pressure due to the keep fill line, and no appreciable rise in pressure was observed. The inspector agreed that this test proved that the postulated overpressure concern could not occur on this particular system. This item is closed.
>
3.
Exit Meeting The inspection scope ano findings were summarized on October 8, 1993, with those persons indicated in paragraph 1. The inspector described the
'
areas inspected and discussed in detail the inspection results listed below. Dissenting comments were not received from the licensee.
(0 pen)
Violation 50-321,366/91-202, Design Control.
Deficiency 01 remains open. Deficiencies 02, 06 and 07 are closed.
Paragraph 2.1.
(Closed)
Deficiency 03, Fast Transfer Permissive Relay.
Paragraph 2.2.
.
(0pened)
Inspector Followup Item 50-321,366/93-19-01, Operator
,
Guidance for Loading Diesel Generator.
Deficiency 04 was,'
changed to this IFI.
Paragraph 2.3.
(Closed)
Unresolved Item 05, Sizing of 250 VDC/600 VAC Inverters.
Paragraph 2.4.
(0pened)
Inspector Followup Item 50-321,366/93-19-02, Electrical Coordination Problems. Observation 08 was changed to this IFI.
Paragraph 2.5.
(Closed)
Deficiency 09, Discrepancies in Mechanical Design Documentation.
Paragraph 2.6.
(Closed)
Deficiency 10, Plant Service Water System. Paragraph 2.7.
,
i i
l
l