ML16341G222
| ML16341G222 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/01/1991 |
| From: | Rood H Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9108090124 | |
| Download: ML16341G222 (24) | |
Text
~PR AE'00 C'oal Wp0 tip
. pW~
~
g s
0O (X
~**+~
Docket Nos.
50-275 and 50-323 UNITED STATES NUCLEAR REGULATORY CO MMISS ION WASHINGTON, D.C. 20555 August 1, 1991 LICENSEE:
FACILITY
'UBJECT:
Pacific Gas and Electric Company (PG&E)
Diablo Canyon Nuclear Power Plant, Units 1 and 2
SUMMARY
OF JULY 10, 1991 MEETING WITH PACIFIC GAS AND ELECTRIC COMPANY AND GENERAL ELECTRIC COMPANY TO DISCUSS THE CAPABILITY OF THE GENERAL ELECTRIC 4.16-kV CIRCUIT BREAKERS AT DIABLO CANYON TO PERFORM THEIR SAFETY FUNCTION d
On July 10, 1991, the NRC staff met with representatives of the Pacific Gas and Electric Company (PG&E) and the General Electric Company (GE) in Rockville, Maryland to discuss the capability of the 4.16-kV safety-related circuit breakers at the Diablo Canyon Nuclear Power Plant to perform their safety function.
Attendees at the meeting are listed in Enclosure l.
View-graphs presented by PG&E/GE at the meeting are given in Enclosure 2.
The 4.16-kV breaker capacity issue arose during the electrical distribution system functional inspection (EDSFI) conducted by an NRC inspection team at Diablo Canyon from April 22 through May 24, 1991.
The inspection team found that PG&E was in the process of resolving a nonconforming condition (reference NCR DCO-90-EN-032) that PG&E had identified in 1990 when attempting to procure replacement breakers from the breaker manufacturer, GE.
The NCR indicates that the worst case fault current of the system exceeds the short circuit interrupting current nameplate rating of the breakers.
The worst case demand only occurs if a short circuit occurs at the 4.16-kV bus during periodic testing when the diesel generator is connected to the grid.
PG&E had obtained a significant uprating of the breakers from GE in 1983, but this was retracted, at least partially, in 1990.
During the EDSFI, PG&E argued that operation beyond the nameplate rating is acceptable because the breakers were tested without fai lures, in accordance with ANSI Standar d C37.09, at short circuit currents greater than the nameplate rating.
- However, PG&E was unable to provide the inspection team with test data on the breakers that would demonstrate that their capacity is greater than the demand.
At the July 10, 1991 meeting, GE presented data from testing it had conducted in the 1960s on new breakers.
The data had been given to PG&E when the breakers were originally procured, but the data was not accessible during the EDSFI.
This data is shown in Enclosure 2.
The data indicate that the worst case demand on the breakers at Diablo Canyon is about 8 to 10 percent beyond the nameplate
- value, and that test failures were not observed until the demand was 20 to 30 percent greater than the nameplate value.
At the meeting, GE r 9108090124 910801 PDR ADOCN 05000275 P
PDR (0
I representatives stated that while the test data indicated that additional margin to failure beyond the nameplate rating existed, GE did not plan to change the original nameplate rating of the breaker.
In response to a staff
- question, PGSE stated that there are 19 safety-related 4.16-kV breakers and 6
non-safety-related feeder breakers in each unit at Diablo Canyon.
At the conclusion of the meeting the NRC staff stated that it has reservations about the acceptability of operating a safety-related breaker beyond the nameplate rating due to the potential degradation of breaker capability with the passage of time.
The staff indicated that this issue would be an open item in the EDSFI report (reference Unresolved Item 50-275/91-01-01),
and that the staff wi 11 subsequently pursue its resolution with PGSE.
Enclosures:
- 1. List of Attendees
- 2. View-graphs Presented by PGSE/GE cc w/enclosures:
See next page Harry Ro d, Senior Project Manager Project Directorate V-Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation
I CI
representatives stated that while the test data indicated that additional margin to failure beyond the nameplate rating existed, GE did not plan to change the original nameplate rating of the breaker.
In response to a staff
- question, PGSE stated that there are 19 safety-related 4.16-kV breakers and 6
non-safety-related feeder breakers in each unit at Diablo Canyon.
At the conclusion of the meeting the NRC staff stated that it has reservations about the acceptabil,ity of operating a safety-related breaker beyond the nameplate rating due to the potential degradation of breaker capability with the passage of time.
The staff indicated that this issue would be an open, item in the EDSFI report (reference Unresolved Item 50-275/91-01-01),
and that the staff will subsequently pursue its resolution with PG&E.
Enclosures:
- 1. List of Attendees 2.
View-graphs Presented by PGKE/GE cc w/enclosures:
See next page ORIGINAL SIGNED BY Harry Rood, Senior Project Manager Project Directorate V
Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation
\\
DISTRIBUTION
'RC 5
LPDR PDV Reading FMirag 1 i a JPartlow BBoger MVirgilio LNorrho1m'Huey, RV JDyer HRood ADummer JCaldwell OGC ACRS (10)
EJordan EImbro RZimmerman, RV JKnight KNaidu SSaba J Knox JJacobson FRosa
- WAng, RV DRPW/PDRLA DRPW/P 5/PM DRP D5/D RCesaro HRood 08/4//91 05/0(/91 0$/4/
91
I I 4>a I ~,
~
It Ul 4
l,l ~
.J.st 4
4 ~ I 4
4,
~
4 4
da f4 Ill 44 f I.I I
tl t
>alai UI
',4>4>c '.
'I
.1>i
>'I" al>t 44 4!>
4; 4
4 Hi>pl',
4>l r ai'!
Hl Tav i,
4
')4 I ~
UH aD f.f 4
4
" I ) I "'U.,
4 4
4 II 4
4 It 4 ak "4
,." D ss 4
'(
I, I
4
>fr Il
<<"lIS
~
4 4
4 4'
4 H.lf af:
>,.Hl..
I I!'I al'iv 4
I ts IU 4
s>C
'rl'
~'J
'Ir, UI>s II
~
'4 J I>.." 'f D 4
.4 I
>I
,>I@
IIU'I ll 4'1 "" 4
-'l, 4 II ( H.D..i.>45
,>I'sf '>44
>4 r L>
la ",I 4D>f >
')
IIH
<< I',>>
) f LIU It Hr I
I 4 I ill. 4
<<) >O'.D
(>I ">a)4 JR H.l fa lid'.
I 'D,i J
il I "f I
IIL I 4
4
,.'1fla ~"
v
~
4 4
4 4 44
'll ~
I, It
, Vfa,1l r
~
" 'P'44 (4
'4'4 Ra>
4 II it 4
- lt I 4
1st Ut 4
~
I ii,,sa" lHD" 1 t
4 4
t $
"I I,
4
~
y t,lj 44>U 4
- *]I,)
4>>
44 Utl 4 IR>
4
Mr. J.
D. Shiffer Pacific Gas and Electric Company Di ab lo Canyon CC:
NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.
Box 369 Avila Beach, Cali fornia 93424 Dr. Richard Ferguson, Energy Chair Sierra Club California 6715 Rocky Canyon Creston, California 93432 Ms.
Sandra A. Silver Mothers for Peace 660 Granite Creek Road Santa Cruz, California 95065 Ms. Jacquelyn C. Wheeler 3303 Barranca Court San Luis Obispo, California 93401 Managing Editor The Count Tele ram Tribune 1321 Jo nson Avenue P.
0.
Box 112 San Luis Obispo, California 93406 Chairman San Luis Obispo County Board of Supervisors Room 370 County Government Center San Luis Obispo, California 93408 Richard F. Locke, Esq.
Pacific Gas 5 Electric Company Post Office Box 7442
- San Francisco, California 94120 Mr. John Hickman Senior Health Physicist Environmental Radioactive Mgmt. Unit Environmental Management Branch State Department of Health Services 714 P Street, Room 616 Sacramento, California 95814 Regional Adminstrator, Region V
U.S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596 Mr. Peter H.
Kaufman Deputy Attorney General State of California 110 West A Street, Suite 700 San Diego, California 92101 Ms.
Nancy Culver 192 Luneta Street San Luis Obispo, California 93401 Michael M. Strumwasser, Esq.
Special Assistant Attorney General State of California Department of Justice 3580 Wilshire Boulevard, Room 800 Los Angeles, California 90010
ENCLOSURE 1
Attendees July 10, 1991 Meeting to discuss 4.16-kV circuit breaker capability NAME Moy Basu Don Behnke Jim Coleman Ann Dummer Steven Foat Jeff Jacobson Jim Knight John Knox Richard Miller Kamal Naidu Mansfield Heal Harry Rood Saba Saba Raymond Thierry Michael Tresler ORGANIZATION PGRE GE (Walnut Creek, CA)
NRC/DRPW/PD5 PGSE NRC/DRIS/RSIB NRC/DST/SELB NRC/DST/SELB GE (Philadelphia, PA)
NRC/DR IS/RVI B GE (King of Prussia, PA)
NRC/DRPW/PD5 NRC/DST/SELB PGSE PG&E
ENCLOSURE 2
View-Graphs presented by PGIIE/GE July 10, 1991 Meeting to discuss 4.16-kV breaker capability
AGENDA GE 4KV Breaker Short Circuit Capability PGKE GE NRC meeting July 10, 1991
===1.
Background===
2.
ANSI Table I
3.
Data Summary 4.
Symetrical Data Plot 5.
Asymetrical Data Plot 6.
Conclusions
ii
~
I '
~
~
~
. ~ 4 I
~
I
~
~
~
I
~
I
~
I
~
~
I
~
I
~
~
~
~
~
~
~
e I e
~ I I
~
e e
~
~
I
~
~
~
~
~
~
~
I e
I I
~
I I I
I
~
I
~ I e
I I I
~
I I
e I
I I
e
~
~
~
~
~
e
~
~
~
I I
~
I I
~
e
~ I
~
I I
~
e e
~
~
~
I
~
I I I
I
~
I
~
I I I
e I I
~
~
~
~
~
~
~ ~
~
~
~
~
I
~
e I
I I
~
I I I
~
I I
~
e
. I
~
~
~
~
~
~
~
e
~
~
. I
~
~
I
~
I I
~
~
I
~
~
~
e
~
~
I
~
~
e
~
~
~
e
~
I
~
I I
~
I
~
~
~
~
~
~
~
~
I e
~
~
~
(
BREAKERS RATED ON A i fMETRICALCURRENT BASIS ANSI/IEEE C37.09.1979
,3 NOTES:
V is the rated maximum voltage. See 5.1 of ANSI/IEEE C37.04-1979.
I is the rated short circuit current. See 4.10.1 of ANSI/IEEE C37.04-1979.
K is the voltage range factor. See 5.2 of ANSI/IEEE C37.04.1979.
S is the asymmetry factor determined from 5.10.2.2 of ANSI/IEEE C37.04 1979.
B is the factor for reclosing duty cycle determined from 5.10.2.6 of ANSI/IEEE C37.04-1979.
T is the maximum permissible tripping delay (see 5.8.1 of ANSI/IEEE C37.04-1979) and is as near Y as test facilities permit.
(1) The voltage, current, and time values in a test must be equal to or greater than the specified values, except'hat the time values may be reduced at the discretion of the manufacturer.
4.6.5.3.1.)
(2) If imposed by limitations in testing facilities, a tolerance of -5% is permissible in the recovery voltage. (See (3) This value is required in only one operation and in only one phase.
(See 4.6.5.10.)
(4) Obtain the most severe switching conditions on at least one interruption. (See 4.6.5.11.)
~
(5) The connections from the power source shall be moved from one side of the circuit breaker to the other between Test Duties 4 and 6 and between Test Duties 5 and 7 ifthat changes the possibility of fiashover to ground or between phases. (See 4.6.5.9.)
(6) Interrupting time on the last operation may exceed the rated interrupting time by one cycle. For conditions after test, see 4.6,4.3.
(7) Test Duties designated with -2 and -3 constitute an alternate for a Test Duty designated with a corresponding
-l. Alloperations made in performing Test Duties 7A or 7B, either with the -1 Test Duty or the -2 and-3 Test Duties, are to be performed without maintenance to demonstrate that the circuit breaker willbe in the condition specified after performing the number of operations required for the service capability. (See 5.10.3.3 of ANSI/IEEE G37.04-1979.)
If the evidence available from development tests on this circuit breaker shows that a standard duty cycle is more severe with the voltages and currents of Test Duty 7 than of Test Duty 6, Test Duty 6 may'be omitted. Ifthe evi-ence available from development tests on this circuit breaker shows that a standard duty cycle is more severe with the voltages and currents of Test Duty 6 than of Test Duty 7, a modified Test Duty 7, made with the voltages and currents speciifiied for Test Duty 6, may be used in place of both Test Duties 6 and 7.
If the standard duty cycle h not used in either Test Duty 4 or 5 and if neither Test Duty 6-1 nor 7-1 is used as specified, the standard duty cycle shall be demonstrated by Test Duty 6-1 with the currents and recovery voltage as nearly as possible at the required values without any of the values being exceeded except with the agreement of the manufacturer.
Test Duty 6-1 shall then be supplemented by either Test Duty 6-2 or Test Duty 6-3, whichever is necessary to meet the requirement not fully met by Test Duty 6-1. The other part of the alternate Test Duty need not be made.
(8) In the closed position, the circuit breaker shall carry a current having an rms value over 3 s ofZI. For zneasure-ment of current, see 7.1.6.
(9) The average of the rms values of the three ac components shall be equal to or greater than the specified value.
The value of the ac component in any phase shall not vary from the average by more than 10% of the average.
(10) This value is required only in one operation, but in all three phases.
(ll)Test Duties 9 and 10 are omitted if the circuit breaker is not rated for instantaneous reclosing. The reclosing time should not exceed the rated relcosing time. See 5.9 of ANSI/IEEE C37.04-1979.
(12) This test may be omitted ifK is less than 1.2.
(13) This service capability test is required only on circuit breakers demonstrated with Test Duty 7B because a
duty at least equivalent is required in 7A. The sum of the currents interrupted in a combined total of 10 or less O and CO operations shall be equal to at least 400% ZSI. In this series, except in the final op~ration, no individual symmetrical component siiould exceed 0.85 KI, nor should any individual total rms current exceed 0.85 KSI. In the final operation, the circuit breaker must clear a current having a symmetrical component at least equal to KI, but the interrupting time may exceed the rated interrupting time by one cycle. See 4.6.4.3. At the discretion of the znanu-facturer, this Test Duty may be met by running without maintenance Test Duties 1 to 3, inclusive; plus such other opening operations at any currents as may be required to make up an accumulated interrupted currenbef 400% ZSI and then after 1 h making one clos~pen operation with a current having a symmetrical component at least equal to Zl. See 5.10.3.3 of ANSI/IEEE C37.04-1979 for limitation on tests per hour and 4.6.4.3 for condition after test.
(14) The neutral of the test circuit or the shozt circuit shall be grounded, but not both.
(15) In the Test Duty or Test Duties used to demonstrate the standard duty cycle and service capability between 85 and 100% of the required asymmetrical intezrupting capability, the 15 s time interval shall be used. Unless other-wise specified, for reclosing and service capability demonstrations, all other Test Duties may be made with longer intervals or with corresponding operations not made in sequence.
Successive open or close operations require intervening switching of the testing circuit.
(16) Befoze at least 'one close operation in one Test Duty, the closing and tripping test voltages shall be at their respective minimums and the operating pressures of'neumatic or hydraulic operating mechanisms shall be 106% or less of cut-off pressure.
(17) A compressed gas circuit breaker shall make two close. open operations at the required interrupting capability without the arc extinguishing medium being replenished.
This may be demonstrated during Test Duty 4 or 5 by shutting off the air supply before the CO-15 s-CO operating duty or before the circuit breaker is closed prior to either one of the operations with the pressure corresponding to that of the second operation in these Test Duties. In this last case, the air may be replenished between operations.
(18) Either Test Duty 4 or Test Duty 5 may be omitted if the evidence available from development tests on this circuit breaker shows that the other is the more severe condition.
(19) The bus should have a capability of I or Kl and the test current reduced by additional line impedance to the required values.
(20),All test duties should be made with transient recovery voltages as specified in 4.7.
(21) This demonstration test is not required for circuit breakers rated 72.5 kV and below.
21
ll
(
i J
I
~
0 I
~
I
)
~
Il 0 ti
( ~
4
~
Vg 9
y J
~
F~
e' e
C
~
j s
~
S
V
TABLE 1 AM4.16-250 TESTS ANSI Line 4 Phase S m.
Asm.
Y V/K KA 4i-'Tests Comment 4
5 11 13 13 13 13 13 13 13 3
X X
32 3
X X
36 3
X 31 X
33 X
20 1
X 29 1
X 34 1
X 38 X
39 X
39 2
2 2
2 Z
3 2
1 FAILS 6
7B 8
9 10 14 14 14 14 14 3
3 3
3 3
1 1
1 X
X X
X X
X X
X
.58V X
.58V X
.58Y X
.58V X
.58V X
X 27 32 35 25 28 30 20 30 35 39 2
3 30,31, &32KA 5 22.6, 22.6, 23.6, 23.6, &35KA 2
2 27 &28KA 2 29 &30 KA 1
1 1
1 FAILS
E I