ML20010J620
| ML20010J620 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 09/24/1981 |
| From: | Aswell D LOUISIANA POWER & LIGHT CO. |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, W3K81-0345, W3K81-345, NUDOCS 8110060264 | |
| Download: ML20010J620 (7) | |
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LOUISIANA 142 DELARONDE STREET POWER & L1GHT P O BOX 6000
- NEW ORLEANS. LOUISIANA 70174 (504) 366 2345
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usSNbsY[U D L ASWELL September 24, 1981 vc. m etw %=toi W3K81-0345 Q-3-A35.07.36 n-hA34 02.01 9
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Mr. K. V. Seyfrit, Director, Region IV
< j f- @ 2 81981 U. S. Nuclear Regulatory Commission o
Ik Office of Inspece*~n and Enforcement p
611 Ryan Plaza Drive, Suite 1000
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j Arlington, Texas 76012 a
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Subject:
Waterford SES Unit No. 3 Docket No. 50- 382 Interim Report of Significant Construction Deficiency No. 36 "Short Circuit Bracing in GE Vertical Lift Metal-Clad Switchgear Equipment"
Reference:
relcon:
L. L. Bass (LP&L) to R. Hall (NRC) dated August 28, 1981
Dear Mr. Seyfrit:
In accordance with the requirements of 10CFR50.55(e), we are hereby providing two copies of the Interim L port of Significant Construction Deficiency No. 35, "Short Circuit Bracing in GE Vertical Lift Metal-Clad Switchgear Equipment".
If you have any questions, please advise.
Very truly yours, c,V h 0
D. L. Aswell p
g DLA/LLB/grf
- 2 OOT F 1
Attachment Dj I
cc:
- 1) Director "J'l.I', g @
Office of Inspection & Enforcement N/fs U. S. Nuclear Regulatory Commission Washington, D. C. 20555 (with 15 copies of report)
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- 2) Director Office of Management IIIl Information and Program Control l
U. S. huclear Regulatory Commission Washington, D. C. 20555 (with I copy of report) g110060264810924 R ADOCK 05000382 S
I LOUISIANA POWER AND LIGHT COMPAhT WATERFORD SES UNIT NO. 3 INTERIM REPORT OF SIGNIFICANT CONSTRUCTION DEFICIENCY No. 36 "SHORT CIRCUIT BRACING IN CE VERTICAL LIFT METAL-CLAD SWITChGEAR EQUIPMENT" 9!'7!8/
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Reviewed by J P Padalino - Project Engineer Date Reviewed by b Lf A t kee T\\. b bl-9
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J DeBruin - ESSE Project Engineer Data Reviewed by b1
.i K Fojt - Licensing Engineer
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A Beninati -
lity Assurance Engineer / Dyfte Reviewed by
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B Esnes - Site Lead Discipline Engineer Date SEPTDtBER 16, 1981 l
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INTERIM REPORT OF SIGNIFICANT CONSTRUCTION DEFICIENCY No. 36 "SHORT CIRCUIT BRACING IN GE VERTICAL LIFF METAL-CLAD SWITCHGEAR EQUIPMENT" Introduction This report is submitted pursuant to 10CFR50.55(e).
It describes a deficiency in the short circuit bracing designs on soae vertical lift metal-clad switchgear equipment supplied by General Electric. This problem is considered reportable under the requirements of 10CFR50.55(e). To the best of our knowledge, this problem has not been identified to the Nuclear Regulatory Commission pursuant to 10CFR21.
Description of Problem On August 14, 1981, General Electric Company notified Ebasco Services Incorporated that requalification tests have indicated that the short circuit bracing designs on some vertical lift metal-clad switchgear equipment do not have their intended short circuit withstand (momentary) capability of 80,000 amperes. The rain bus and runback supports in these designs are unabic to withstand the full short circuit rating assigned to this equipment without some damage to the bus supports and potential additional problems due to the weakening of such aupports.
It should be emphasized that these problems have been discovered during tests.
GE has no record of any field failures caused by short circuit currents imposed on this equipment.
This lack of field failures is to be expected as only very unusual applications require capability in excess of 50,000 amperes, Safety Implications Specification No. 1564.259B under which the switchgear was procured calls for main bus short circuit withstanding capacity of 78 kA.
The actual capacity 50 kA verified by tests is not adequate.
In case of over current exceeding 50kA, the resulting dynamic forces would mechanically damage the main bus of the effected safety-related switchgear and put it out of operation for a long term period.
The loss of the redundant electrical support system would impose limiting condi-tions on the operation of the plact. According to Technical Specification 3.8.2.1, when inoperability exceeds eight (8) hcurs, the plant should be put in hot stand-by within the next six (6) hours and in cold shutdown within the following thrity (30) hours. Therefore, the deviation from required performance exists and is significant because it would adversely affect the safety of the plant if left uncorrected and as such in reportable.
O Corrective Action Field modifications have been submitted by GE and are available for those units which require high withstand capability. These modifications consist of:
1.
Additional supports in some main bus arrangements to prevent possible damage to the unit line bus supports. The damage seen in the requalification tests would not be suf ficient to cause an immediate malfunction, but it does leave the supports in a weakened condition and subject to further deterioratlon both dielectrically and physically.
2.
Stiffer supports at the rear end of the C.T. runback supports.
Failure of this support could cause severe damage. GE has changed out designs to call for h" chick supports f or momentary requirements above 6o,000 amperes.
3.
An additienal support at the front end oi the C.T. runback bars in the vicinity of the rear primary disconnect in order to prevent excessive loading on the rear primary porcelains when the momentary current available is in excess of 66,000 amperes.
GE has reviewed the design of the equipment furnished to us en Requisition No. 300-88691 and has noted some units in which the above modifications should be made in order to bring the short circuit bracing up to the full rating of 80,009 amperes for 10 cycles.
Kits of parts and necessary instructions are being furnished at the Waterford site to carry out the required modifications.
4 Materials for corrective action will be shipped from GE to the site in October.
l This problem is documented on Ebasco Nonconformance Report '43-2344.
Corrective Action is scheduled for completion by October 30, 1981. The final report will be submitted on or before November 30, 1981.
l l
1 I
r LOUISIANA POWER AND LIGHT COMPANY WATERFORD SES UNIT NO. 3 INTERIM REPORT OF SIGNIFICANT CONSTRUCTION DEFICIJ CY NO. 36 "SHORT CIRCUIT BRACING IN GE VEP.TICAL LIFT METAL-CLAD SWITCHGEAR EQUIPMENT" Reviewed by e On 1,
9/7!8/
J P Padalino - Project Engineer Date '
Reviewed by b, l)'
5 koy 7\\. b b.j-9(O Ok J DeBruin - ESSE Project Engineer Data 4
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f r
t!f7 k Reviewed by k1 I
_m K Fojt - Licensing Engineer
' Date Reviewed by
/m 7/ /4/8/
A Beninati -
lity Assurance Engineer / Dgte h.U M/ L S be:
9l0 s(
Reviewed by B Esnes - Site' Lead Discipline Engineer Date SEPTEMBER 16, 1981
a INTERIM REPORT OF SIGNIFICANT CONSTRUCTION DEFICIENCY NO. 36 "SHORT CIRCUIT BRACING IN GE VERTICAL LIFT METAL-CLAD SWITCH 0 EAR EQUIPMENT" Introduction This report is submitted pursuant to 10CFR50.55(e).
It describes a deficiency in the short circuit bracing designs on some vertical lif t metal-clad switchgear equipment supplied by General Electric. This problem is considered reportable under the requirements of 10CFR50.55(e). To the best of our knowledge, this problem has not been identified to the Nuclear Regulatory Commission pursuant to 10CFR21.
Description of Problem On August 14, 1981, General Electric Company notified Ebasco Services Incorporated that requalification tests have indicated that the short circuit bracing designs on some vertical lift metal-clad switchgear equipment do not have their intended short circuit withstand (momentary) capability of 80,000 amperes. The main bus and runback supports in these designs are unable to withstand the full short circuit rating assigned to this equipment without some damage to the bus supports and potential additional problems due to the weakening of such supports.
It should be emphasized that these problems have been discovered during tests.
GE has no record of any field failures caused by short circuit currents imposed on this equipment. This lack of field failures is to be expected as only very unusual l
applications require capability in excess of 50,000 amperes.
Safety Implications Specification No. 1564.259B under which the switchgear was procured calls fer main bus short circuit withstanding capacity of 78 kA.
The actual capacity 50 kA verified by tests is not adequate. In case of ever current exceeding 50kA, the resulting dynamic forces would mechanically damage the main bus of the effected safety-related switchgear and put it out of operation for a long term period.
The loss of the redundant electrical support system would impose limiting condi-tions on the operation of the plant. According to Technical Specification 3.8.2.1, when inoperability exceeds eight (8) hours, the plant should be put in hot stand-by within the next six (6) hours and in cold shutdown within the following thrity (30) hours. Therefore, the deviation from required performance exists and is significant because it would adversely affect the safety of the plant if left uncorrected and as such is reportable.
r~
-~
Corrective Action Field modifications have been submitted by GE and are available for those units which require high withstand capability. These mcdifications consist of:
1.
Additional supports in some main bus arrangements to prevent possible damage to the unit line bus supports. The damage seen in the requalificatioit tests would not be sufficient to cause an immediate malfunction, but it does leave the supports in a weakened condition and subject to further detericration both dielectrically and physically.
2.
Stiffer supports at the rear end of the C.T. runback supports.
Failure of this support could cause severe damage. GE has changed out designs to call for " thick supports f or momentary requirements above 66,000 amperes.
3.
An additional support at the front end of the C.T. runback bars in the vicinity of the rear primary disconnect in order to prevent excessive loading on the rear primary porcelains when the momentary current availabic is in excess of 66,000 amperes.
GE has reviewed the design of the equipment furnished to us on Requisition No.'300-88691 and has noted some units in which the above modifications should be made in order to bring the short circuit bracing up to the full rating of 80,000 amperes for 10 cycles.
Kits of parts and necessary instructions are being furnished at the Waterford site to carry out the required modifications.
Materials for corrective action will be shipped from GE to the site in October.
This problem is documented on Ebasco Nonconformance Report W3-2344. Corrective Action is scheduled for completion by October 30, 1981. The final report will be submitted on or before November 30, 1981.