ML19220C356
| ML19220C356 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/04/1974 |
| From: | John Miller Metropolitan Edison Co |
| To: | Knuth D US Atomic Energy Commission (AEC) |
| Shared Package | |
| ML19220C355 | List: |
| References | |
| NUDOCS 7904300469 | |
| Download: ML19220C356 (2) | |
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ST OFFICE EOX 542 REACING, PENNSYLVANI A 195C3 TELEPHCNE 215 - 329 ;601 February L, 197L Dr. D. R. Ynuth, Director Directcrate of Regulatory Operaticas United States Atc=le Energy Cc =ission Washfngton, D. C.
20545
Subject:
Three Mile I.aland Units 1 and 2 Docket Nos%__50-25^9;1nd 50-320
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Reactor Suilding Spray Pu=p Motors
Dear Dr. Knuth:
You were notified en January 3, 1974, of a situatien uhich =2y be censidered reportable under 10CFR50.55(e), "Conditicas of Constructica".
This situation related to Reactor Building Spray Pu=p Motors.
DESCRIPTION OF I'; CIDE';T The =anufacturer of the Three M.ile Island Unit 1 Reactor Building Spray Pu=p Motors advises that the starting ti=e of these ctors does not the require =ents of the purchase order specification.
=cet The =otors are 250 horsepower, 4000 volt, 60 H, 3600 RPM scuirrel 2
cage water eccled =oters =anufactured by Westinghouse's 3uffalo plant.
These =ctors are identified by Westinghcuse shcp crder No. 68F2C805.
The purchase order specificarica required these motors to "accelelate their driven lead to nor=al operating speed within six seconds ce the worst voltage condition (i.e., 80% of rated voltage at the =ctor ter=inals)."
Westinghouse advises that the ti=e required to accelerate lead is as shown below:
Volta 2e, *:
Acceleratice Ti=e. Sec. 100 3.9 90 6.0 85 7.8 80 11.4
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An analysis of the Engineered Safeguards Cicsel Generater leading has been perforned by Gilbert Associates, Inc.
The Reactor Building Scray Pu=p Motors are loaded as part of Block 4 ef the engineered safcaucrds loading sequence as indicated on Tabic 3-1 cf the FSAR.
When Block 4 is connec cd to the diesel generator, the initial bus voltage =ccentarily decreases to 83% (3453 sol:s) of the ncr:21 bus voltage (4160 volts).
This is app cx1-
=ctely 86% of the =ctor rated voltages of 4000 V.
Based en the data sub=itted b~y the diesel generator =anufacturer, the high speed diesel ganerator exci:c will retur: the bus to full rated voltage in 1.12 seconds.
The total ti=e for =otor accelaration at 1C0% voltage, pit' the ti=e diesel generator is below 100% voltage, is 1.12 seccnds plus 3.9 set snds, a total cf 5.02 seconds.
This 5.02 second accelera:ica time =cets the intent of the pn: chase order specification, i.e., full loaded =otor acceleratica within six seccnds.
The diesel generator as the pcwer source represents the worst case condition for starting the subject spray pu=p :otors.
COu.b..CTIV E ACTiOS' buoPM Fn OR '*3vr" Unit 1 No corrective action is required.
Verification of Reactor Building Spray Pu=p and =ctor perfor:ance will be dc=enst sted during the Integrated Engineered Safeguards Activa:1cn Test (!?600/21).
Unit 2 The =oters for the Three Mile Island Unit 2 Reactor Buildir.._ Spray Pu=ps are identical in type to the Three Mile Island Uni 1 :oters.
The load characteristic is =cre severe, hewever, due :: the use of a different pu=p en Three Mile Island Unit 2.
This core severe leading results in acceler2:ica ti=es that are lenger than these reported for the Three Mile Island Unit 1
=otors.
These =otors have censequently been returned to Westinghouse for testing at voltages down to 80% of rated voltage.
A decisica on the =ethod of solutica to the Three Mile Island Uni: 2 ::ter proble: will be =ade af: r the =easured acceleration ti=es are available.
Very truly yours, I
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G. Miller brh Vice President ec:Mr. J. P. O'Railly Mr. W. A. Ver:Ochi n, '."
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