ML20080P280
| ML20080P280 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 09/30/1983 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 5211-83-260, NUDOCS 8310060390 | |
| Download: ML20080P280 (5) | |
Text
o Nuclear
=" "c r" "
Route 441 South Middletown, Pennsylvania 17057-0191 717 944 7621 TELEX 84 2386 Writer's Direct Dial Number:
I September 30, 1983 5211-83-260 Office of Nuclear Reactor Regulation Attn:
J. F. Stolz, Chief Operating Reactors Branch No. 4 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Sir:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. OPR-50 Docket No. 50-289 Degraded Grid Voltage Test The NRC Staff safety evaluation for Amendment 70 to the TMI-1 Technical Specifications dated July 29, 1981, documented a Met-Ed commitment to provide measured bus IT after testing the onsite safety related electrical distribution system.
The measured bus voltages for the safety related motor control centers and 480 volt safety bus voltages were identified by the staff as being needed to verify the accuracy of the analyzed voltage drops between the previously verified busses and those that were not provided in Met-Ed letter dated May 23, 1980 (Ref. 1 ).
The distribution system test was conducted on September 5, 1981.
It was performed with and without loss of offsite power on engineered safeguards (ES) red channel
'A'.
ES Channel
'B' was assumed to be unavailable for the purpose of this test.
Current and potential circuits were run through test blocks, transducers and signal conditioners to both magnetic and strip chart recorders.
During the test, class-IE electrical power system received power from primary 230kv electrical power system.
The engineered safeguards signal was manually activated from the control room which initiated safeguards block loading.
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The following parameters were recorded during the test:
oo (1)
Kilowatt, voltage and current recorders on the following buses:
o a.
1D-ES 4160V switchgear bus b.
IP-ES 480V switchgear bus oQ oO (II)
Voltage and current recorders were connected on the following a-engineered safeguards buses:
Ob GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation
Mr. John F. Stolz 5211-83-260 4
a.
lA-ES 480V motor control center b.
lA-ES 480V valve control center c.
IC-ES 480V valve control center d.
lA-ES (SH) 480V motor control center j
On June 10, 1983, GPUN representatives contacted the NRC concerning the test (TP-622/1) and informed them that bus IT was not included in the test because the bus is not fed from the red channel, channel
'A'.
The NRC then requested that instead of supplying.the information referred to in the staff SER supporting Amendment 70, GPUN should supply a comparison of branch Technical l
Position PSB-1, Rev.1 July 1981, " Adequacy of Station Electric Distribution System Voltages", with the test performed at TMI-1.
This comparison is provided in Table 1 (attached).
4 Finally, the following three cases have been reviewed for comparing the l
analyzed and measured bus voltage (Table 2, attached).
a.
Offsite power available, starting ES block 1.
b.
Offsite power available, running ES block 1.
c.
Offsite power available, running one full ES train.
The results of the test support the previous analysis submitted by Ref.
1.
The acceptability of the voltage conditions and the undervoltage relay T
setting on the TMI-l safety electric distribution system has bean recon-firmed by the actual test where the variation between measured and calculated i
i voltage was well within the PSB-1 stated limits.
Sincerely, kH. D. HLkill 2'
Director, TMI-l HDH:LWH:vjf Reference 1:
Met-Ed letter dated May 15, 1980 (TLL 224) l cc:
R. Conte J. Van Vliet I
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Table 1 Comparison of BTP-PSBl Recommendations and Tl1I-l Test Conditions BTP-PSB-1 Recommendations Till-1 Test Conditions a) loading the station distri-a) The station class lE buses bution buses, including all were loaded from 68.4% to class lE buses down to the 100% of the analytical load 120/208V level, to at least values (TDR 185). All non-lE 30%;
buses were not loaded to 30%
-of.the_ir bus rating. The plant' was in cold shutdown mode during this test. No class lE 120V AC buses com-parison has been made.
Normal loads were on the 120/
208V buses during the test.
b) recording the existing grid b) The test recorded th' effect and class lE bus voltage and of starting a large class-lE bus loading down to the motor. The grid voltage 120/208V level at steady during the test was re-state conditions and during corded. No large non-class the starting of both a large lE motor was started.
class lE and non-class lE motor (not concurrently) c) using the analytical tech-c) Using the analytical tech-niques and assumptions of the niques of the previous vol-previous voltsge analysis, tage analysis (Ref. 1), a new.
l and the measured existing set of voltages for all the grid voltage and bus loading clast lE buses down to 480 l
conditions recorded during Volt level were calculated.
l conduct of the' test, cal-culate new set of voltages for ali the class lE buses down to the 120/EOSV level; l
l d) compare the analytical de,
d)
ES buses voltages during the i
rived voltage values against:
test were not more than 1.1L the test results lower than the analytical results which were obtained The test results should not by using the same computer be more than 3% lower than program as previously used in the analytical results; how-Ref. 1.
ever, the difference-between the two when subtracted from the voltage levels. determined in the originar analysis--
should never be less than the v
class lE'equiprent rated.vol-tages.
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Table 2 Case 1 - Offsite Power Available, starting I
ES Block 1 ITEM DESCRIPTION ANALYZED RECORDED
% ERROR (BUS)
BUS BUS 6
M x 100 VOLTAGE VOLTAGE B
(A)
(B) 1 BUS 1D 3963.3 3920
+ 1.1%
(4160V SWGR.)
2 BUS 1R 452.3 448
+ 1.0%
(480V SWGR.)
3 BUS IP 441.9 448
- 1.4%
(480V SWGR.)
4 1A SH 452.2 448
+.9%
- 1.8%
- 1.5%
7 1C VCC 440.6 448
- 1.7%
l Case 2 - Offsite Power Available, running ES Block 1 ITEM DESCRIPTION ANALYZED RECORDED
% ERROR (BUS)
BUS BUS A-B g,
x 100 VOLTAGE VOLTAGE B
(A)
(B) 1 BUS 1D 4018 4018
- 0. %
(4160V SWGR.)
2 BUS 1R 458.6 459
- 0.1%
(480V SWGR.)
3 BUS 1P 448.2 460
- 2.6%
(480V SWGR.)
4 1A SH 458.6 459
- 0.1%
(MCC) l 5
1A ES VCC 446.2 453
- 1.5%
l 6
- 1.4%
l l
7 1C VCC 446.9 448
- 0.2%
l i
i
~
Table 2 (Continued)
J Case 3 - Offsite Power Available, running one full ES train.
4 ITEM DESCRIPTION ANALYZED RECORDED
% ERROR (BUS)
BUS BUS A-B g
x 100 VOLTAGE VOLTAGE B
(A)
(B) 1 BUS ID 3991.3 4018
.7%
(4160V SWGR.)
2 BUS 1R 450.3 459
- 1.9%
(480V SWGR.)
3 BUS 1P 442.0 460
- 3.9%
(480V SWGR.)
4 1A SH 450,3
.459
- 1.9%
- 2.9%
- 2.8%
7 1C VCC 440.7 448
- 1.6%
4 7
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