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| issue date = 10/05/1994
| issue date = 10/05/1994
| title = LER 93-014-02:on 930722,determine 4 Kv Vital Bus Second Level Undervoltage Protection Dropout Setpoint Would Not Protect Motors.Detailed Study Showed Motors Would Have Performed Intended Safety functions.W/941005 Ltr
| title = LER 93-014-02:on 930722,determine 4 Kv Vital Bus Second Level Undervoltage Protection Dropout Setpoint Would Not Protect Motors.Detailed Study Showed Motors Would Have Performed Intended Safety functions.W/941005 Ltr
| author name = HAGAN J J, PASTVA M J
| author name = Hagan J, Pastva M
| author affiliation = PUBLIC SERVICE ELECTRIC & GAS CO. OF NEW JERSEY
| author affiliation = PUBLIC SERVICE ELECTRIC & GAS CO. OF NEW JERSEY
| addressee name =  
| addressee name =  
Line 16: Line 16:


=Text=
=Text=
{{#Wiki_filter:e Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 Salem Generating Station U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555  
{{#Wiki_filter:e OPS~G Public Service Electric and Gas Company           P.O. Box 236 Hancocks Bridge, New Jersey 08038 Salem Generating Station October 5, 1994 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC                           20555


==Dear Sir:==
==Dear Sir:==
SALEM GENERATING STATION LICENSE NO. DPR-70 DOCKET NO. 50-272 UNIT NO. 1 October 5, 1994 SUPPLEMENTAL LICENSEE EVENT REPORT 93-014-02 This submittal is made to reclassify an occurrence as a Voluntary Report for informational purposes.
 
This occurrence had been previously identified as reportable pursuant to Code of Federal Regulations lOCFR 50.73. MJPJ:pc Distribution -4 i i I . '.. J..-: ........ v vu-(; v l11e power is in your hands. 9410200158 941005 PDR ADOCK 05000272 s Sincerely yours, 95-2189 REV 7-92 FORM 366 .S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COME'LY WITH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001 AND TO THE. PAPERWORK REDUCTION PROJECT (31S0-0104), OFFICE OF (See reverse for required number of digits/characters for each block) MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. FACILITY NAME (1) DOCKET NUMBER (2) II PAGE (3) Salem Generating Station -Unit 1 05000 272 1 OF 04 TITLE (4) Voluntary Reporting of 4 Kilo-Volt Vital Bus Second Level Undervoltage (UV) I Protection DroJout Setvoint.
SALEM GENERATING STATION LICENSE NO. DPR-70 DOCKET NO. 50-272 UNIT NO. 1 SUPPLEMENTAL LICENSEE EVENT REPORT 93-014-02 This submittal is made to reclassify an occurrence as a Voluntary Report for informational purposes. This occurrence had been previously identified as reportable pursuant to Code of Federal Regulations 10CFR 50.73.
EVENT DATE (5) LER NUMBER f6 REPORT NUMBER f7) OTHER FACILITl!':S INVOLVED (8) SEQUENTIAL REVISION FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NUMBER MONTH DAY' YEAR 05000 311 Salem Unit 2 FACILITY NAME DOCKET. NUMBER ----05000 07 22 93 93 014 02 .10 05 94 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check one or more (11) *MODE (9) 1 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73:71(b) I I 80 I 20.405(a)(1)
Sincerely yours, MJPJ:pc Distribution
: 0)
                ...,nnr.---~
* 50.36(c)(1)
                . .~. . v-4 ivu-(;
: 50. 73 (a)(2)(v) 73.71 (c) 20.405 (a)(1 )(ii) 50.36(c)(2)  
i I . '.. J..-:
.** 50.73(a)(2)(vii) x OTHER I -20A05(a)(1)(iii)
v l11e power is in your hands.
: 50. 73 (a)(2)(i) 50.73(a) (2) (viii) (A) (Specify in Abstract 20.405(a)
9410200158 941005 PDR ADOCK 05000272                                   95-2189 REV 7-92 s
(1) (iv) 50.73(a)(2)(ii)
 
: 50. 73 (a)(2)(viii)(B) below and in Text, NRC Form 366A) 20.405 (a)(1 )(v) 50.73(a)(2)(iii) 50.73(a)(2)(x)
N~C      FORM 366                                         .S. NUCLEAR REGULATORY COMMISSION                               APPROVED BY OMB NO. 3150-0104 (5-92)                                                                                                                               EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COME'LY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.                 FORWARD LICENSEE EVENT REPORT (LER)                                                          COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001 AND TO THE. PAPERWORK REDUCTION PROJECT (31S0-0104), OFFICE OF (See reverse for required number of digits/characters for each block)                         MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.
Voluntarv J LICENSEE:CONTACT FOR THIS LER (12). NAME .. TELEPHONE NUMBER (Include Area Code) M. J. Pastva, Jr. -LER Coordinator (609) 339-5165 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) CAUSE SYSTEM. COMPONENT MANUFACTURER REPORTABLE CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE TONPRDS TO NPRDS *' ' SUPPLEMENTAL REPORT EXPECTED 14 EXPECTED MONTH DAY YEAR I YES NO SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE) x DATE (15) ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16) On 7/22/93, it was determined that the 91. 6% dropout set point for second level undervoltage protection of both Salem Units' 4* kilovolt (KV) vital buses would not fully protect the 230 and 460 volt (V) motors should the 4KV bus voltage degrade to less than 93.2%, but greater than 91. 6%. At that time it was concluded the intent of the Updated Final Safety Analysis Report and guidance provided in "Safety Evaluation And Statement Of Staff Positions Relative To The Emergency Power Systems For Operating Reactors" NRC letter, dated 6/2/77, were not fully met. Continued operation of both Sa_lem Uni ts was based upon self-imposed administrative controls on 4KV bus p.lignment until implementation of design changes to change the dropout setpoint.
FACILITY NAME (1)                                                                                               DOCKET NUMBER (2) 05000 272 II PAGE (3)
A subsequent detailed study shows the motors would have performed their intended safety functions with the 91. 6% setpoint.
Salem Generating Station - Unit 1                                                                                                                                     1 OF   04 TITLE (4)       Voluntary Reporting of 4 Kilo-Volt Vital Bus Second Level Undervoltage (UV)
As such, this report is made voluntarily for informational purposes.  
Protection DroJout Setvoint.
-NRG FORM 366 (5-92)
EVENT DATE (5)                         LER NUMBER f6                     REPORT NUMBER f7)                           OTHER FACILITl!':S INVOLVED (8)
BLOCK NUMBER 1 2 3 4 5 6 7 8 9 10 11 12 13 ' 14 15 REQUIRED NUMBER OF DIGITS/CHARACTERS FOR EACH13LOCK NUMBER OF DIGITS/CHARACTERS TITLE UP TO 46 FACILITY NAME 8 TOTAL 3 IN ADDITION TO 05000 DOCKET NUMBER VARIES 'PAGE NUMBER ''* UP T076 TITLE 6TOTAL 2 PER BLOCK EVENT DATE 7 TOTAL 2 FOR YEAR 3 FOR SEQUENTIAL NUMBER LER NUMBER 2 FOR REVISION NUMBER 6 TOTAL 2 PER BLOCK REPORT DATE UP TO 18 FACILITY NAME 8 TOTAL -DOCKET NUMBER OTHER FACILITIES INVOLVED 3 IN ADDITION TO 05000 1 OPERATING MODE . -3 POWER LEVEL 1 CHECK BOX THAT APPLIES REQUIREMENTS OF 10 CFR UP TO 50 FOR NAME 14 FOR TELEPHONE LICENSEE CONTACT CAUSE VARIES 2 FOR SYSTEM 4 FOR COMPONENT EACH COMPONENT FAILURE 4 FOR MANUFACTURER NPRDS VARIES .. 1 CHECK BOX THAT APPLIES SUPPLEMENTAL REPORT EXPECTED 6 TOTAL 2 PER BLOCK EXPECTED SUBMISSION DATE .
I FACILITY NAME                             DOCKET NUMBER SEQUENTIAL          REVISION MONTH         DAY       YEAR     YEAR                                         MONTH        DAY'   YEAR NUMBER            NUMBER Salem Unit 2                               05000 311 FACILITY NAME                               DOCKET. NUMBER
VOLUNTARY LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 1 DOCKET NUMBER 5000272 PLANT AND SYSTEM IDENTIFICATION:
                                          --                   --                                                                                           05000 07           22       93       93             014               02     .10             05     94 OPERATING                     THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check one or more (11)
Westinghouse
  *MODE (9)                 1       20.402(b)                               20.405(c)                                   50.73(a)(2)(iv)                     73:71(b)
-Pressurized Water Reactor LER NUMBER 93-014-02 PAGE 2 of 4 Energy Industry Identification System (EIIS) codes are identified in the text as {xx} REPORT IDENTIFICATION:
I L:~E~~~O) I 80 I 20.405(a)(1) 0)
Voluntary Reporting Of 4 Kilo-Volt Vital Bus Second Level Undervoltage (UV) Protection Dropout Setpoint Date of Discovery:
* 50.36(c)(1)                                 50. 73 (a)(2)(v)                   73.71 (c) 20.405 (a)(1 )(ii)                       50.36(c)(2)                                 50.73(a)(2)(vii)               x   OTHER 20A05(a)(1)(iii)                         50. 73 (a)(2)(i) 50.73(a) (2) (viii) (A)         (Specify in Abstract I below and in Text, NRC 20.405(a) (1) (iv)                       50.73(a)(2)(ii)                             50. 73 (a)(2)(viii)(B)         Form 366A) 20.405 (a)(1 )(v)                       50.73(a)(2)(iii)                           50.73(a)(2)(x)                   Voluntarv J LICENSEE:CONTACT FOR THIS LER (12).
7/22/93 Report Date: 10/5/94 This report was initiated by Incident Report No. 93-320. INITIAL"CONDITIONS:
NAME                                                                                                         ..         TELEPHONE NUMBER (Include Area Code)
Unit 1: Mode 1 Reactor Power 80% -Unit Load 815 MWe Unit 2: Mode 1 Reactor Power 100% Unit Load 1140 MWe DISCUSSION:
M. J. Pastva, Jr. - LER Coordinator                                                                                       (609) 339-5165 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
On July 22, 1993, an initial determination was made that the 91.6% dropout setpoint for second level undervoltage protection of both Salem Units' 4 kilovolt (KVJ vital buses* {VJ}, would not fully protect the 230 and 460 volt (V) motors should the 4KV bus voltage degrade to less than 93.2%, but greater than 91.6%. At that time it was concluded the intent of the Updated Final Safety Analysis Report {UFSAR) and guidance provided in "Safety Evaluation And Statement Of Staff Positions Relative To The Emergency Power Systems For Operating Reactors" NRC letter, dated June 2, 1977, were not fully met. This was identified during a self-initiated adequacy review to ensure the intent of the 1977 NRC letter was being met. Continued operation of both sa.lem Units was based upon ensuring that the 4KV bus voltage would be maintained at or above 93.2% by imposition of additional administrative controls on 4KV bus alignment until implementation of design changes to change the dropout setpoint.
REPORTABLE                                                                                        REPORTABLE CAUSE       SYSTEM.       COMPONENT       MANUFACTURER                                           CAUSE       SYSTEM       COMPONENT         MANUFACTURER TONPRDS                                                                                           TO NPRDS SUPPLEMENTAL REPORT EXPECTED 14                                                                 EXPECTED         MONTH       DAY   YEAR I YES (If yes, complete EXPECTED SUBMISSION DATE) x NO SUBMISSION DATE (15)
The NRC was notified of this determination pursuant to 10CFR50.72(b)
ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)
{l) (ii) (B). In addition, on August 20, 1993, this issue was reported pursuant to the requirements of 10CFR50.73(a)
On 7/22/93, it was determined that the 91. 6% dropout setpoint for second level undervoltage protection of both Salem Units' 4* kilovolt (KV) vital buses would not fully protect the 230 and 460 volt (V) motors should the 4KV bus voltage degrade to less than 93.2%, but greater than 91. 6%. At that time it was concluded the intent of the Updated Final Safety Analysis Report and guidance provided in "Safety Evaluation And Statement Of Staff Positions Relative To The Emergency Power Systems For Operating Reactors" NRC letter, dated 6/2/77, were not fully met. Continued operation of both Sa_lem Uni ts was based upon self-imposed administrative controls on 4KV bus p.lignment until implementation of design changes to change the dropout setpoint. A subsequent detailed study shows the motors would have performed their intended safety functions with the 91. 6% setpoint. As such, this report is made voluntarily for informational purposes.
(2) (ii) (B) and 10CFR50.73(a)
NRG FORM 366 (5-92)
(2) (v) (D) A subsequent detailed study shows the motors would have performed their intended safety functions with the 91.6% setpoint.
 
Therefore, a reportable occurrence with the setpoint, as described, does not 1 
REQUIRED NUMBER OF DIGITS/CHARACTERS FOR EACH13LOCK BLOCK           NUMBER OF TITLE NUMBER      DIGITS/CHARACTERS 1               UP TO 46                FACILITY NAME 8 TOTAL 2                                        DOCKET NUMBER 3 IN ADDITION TO 05000 3                  VARIES                'PAGE NUMBER              ''*    .
..\ VOLUNTARY LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 1 DOCKET NUMBER 5000272 LER NUMBER 93-014-02 PAGE 3 of 4 DISCUSSION: (cont'd) exist pursuant to 10CFR50.72 or 10CFR50.73.
4               UP T076                  TITLE 6TOTAL 5                                         EVENT DATE 2 PER BLOCK 7 TOTAL 2 FOR YEAR 6                                       LER NUMBER 3 FOR SEQUENTIAL NUMBER 2 FOR REVISION NUMBER 6 TOTAL 7                                        REPORT DATE 2 PER BLOCK UP TO 18 FACILITY NAME 8                                        OTHER FACILITIES INVOLVED 8 TOTAL - DOCKET NUMBER 3 IN ADDITION TO 05000 9                    1                    OPERATING MODE 10                  3                    POWER LEVEL 1
11                                        REQUIREMENTS OF 10 CFR CHECK BOX THAT APPLIES UP TO 50 FOR NAME 12                                        LICENSEE CONTACT 14 FOR TELEPHONE CAUSE VARIES 2 FOR SYSTEM 13        4 FOR COMPONENT                EACH COMPONENT FAILURE
      '    4 FOR MANUFACTURER NPRDS VARIES 1
14                                        SUPPLEMENTAL REPORT EXPECTED CHECK BOX THAT APPLIES 6 TOTAL 15                                        EXPECTED SUBMISSION DATE 2 PER BLOCK
 
VOLUNTARY LICENSEE EVENT REPORT (LER) TEXT CONTINUATION          1 Salem Generating Station        DOCKET NUMBER      LER NUMBER        PAGE Unit 1                            5000272          93-014-02        2 of 4 PLANT AND SYSTEM IDENTIFICATION:
Westinghouse  - Pressurized Water Reactor Energy Industry Identification System (EIIS) codes are identified in the text as {xx}
REPORT IDENTIFICATION:
Voluntary Reporting Of 4 Kilo-Volt Vital Bus Second Level Undervoltage (UV) Protection Dropout Setpoint Date of Discovery:  7/22/93 Report Date:   10/5/94 This report was initiated by Incident Report No. 93-320.
INITIAL"CONDITIONS:
Unit 1:   Mode 1    Reactor Power  80% - Unit Load  815 MWe Unit 2:   Mode 1    Reactor Power 100%    Unit Load 1140 MWe DISCUSSION:
On July 22, 1993, an initial determination was made that the 91.6%
dropout setpoint for second level undervoltage protection of both Salem Units' 4 kilovolt (KVJ vital buses* {VJ}, would not fully protect the 230 and 460 volt (V) motors should the 4KV bus voltage degrade to less than 93.2%, but greater than 91.6%. At that time it was concluded the intent of the Updated Final Safety Analysis Report
{UFSAR) and guidance provided in "Safety Evaluation And Statement Of Staff Positions Relative To The Emergency Power Systems For Operating Reactors" NRC letter, dated June 2, 1977, were not fully met. This was identified during a self-initiated adequacy review to ensure the intent of the 1977 NRC letter was being met. Continued operation of both sa.lem Units was based upon ensuring that the 4KV bus voltage would be maintained at or above 93.2% by imposition of additional administrative controls on 4KV bus alignment until implementation of design changes to change the dropout setpoint. The NRC was notified of this determination pursuant to 10CFR50.72(b) {l) (ii) (B). In addition, on August 20, 1993, this issue was reported pursuant to the requirements of 10CFR50.73(a) (2) (ii) (B) and 10CFR50.73(a) (2) (v) (D)
A subsequent detailed study shows the motors would have performed their intended safety functions with the 91.6% setpoint. Therefore, a reportable occurrence with the setpoint, as described, does not
 
..\
VOLUNTARY LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station        DOCKET NUMBER    LER NUMBER        PAGE Unit 1                             5000272       93-014-02       3 of 4 DISCUSSION:   (cont'd) exist pursuant to 10CFR50.72 or 10CFR50.73.
ANALYSIS:
ANALYSIS:
In July 1993, a self-initiated adequacy review concluded the 91.6% . dropout setpoint for second level undervoltage protection of both Salem Units' 4 KV vital buses, would not fully protect 230 and 460V motors. Continued operation of both Salem Units was based upon the following self-imposed administrative controls regarding 4KV bus alignment:
In July 1993, a self-initiated adequacy review concluded the 91.6% .
: 1. Hourly logging of 4KV vital bus voltages, maintained between 4.3KV and 4.5KV. 2. Maintaining only two vital buses energized from their operating transformer, if both the corresponding group buses are on their respective Auxiliary Power Transformer (APT) . 3a. Maintaining three vital buses energized from the operating transformer, if one of the corresponding group buses is transferred to the operating Station Power Transformer (SPT) or 3b. Maintaining three vital buses energized from the operating transformer, if the load which can be transferred from the APTs is reduced by 5 mega volt amps. However, revision 01 to calculation ES-15.00S(Q), "Salem Units 1 and 2 Degraded Grid Study", shows worst case recovery vital bus voltage is 93.2% of 4KV following transfer of the APTs to the SPTs. A subsequent detailed study shows that the 230 and 460V motors will perform their safety functions with the 91.6% setpoint.
dropout setpoint for second level undervoltage protection of both Salem Units' 4 KV vital buses, would not fully protect 230 and 460V motors. Continued operation of both Salem Units was based upon the following self-imposed administrative controls regarding 4KV bus alignment:
As such, the self-imposed administrative controls serve to add greater enhancement to the performance of these motors, from a reliability standpoint.
: 1. Hourly logging of 4KV vital bus voltages, maintained between 4.3KV and 4.5KV.
The initial determination that the 91.6% dropout setpoint did not meet the intent of the UFSAR and the BTP resulted from overly restrictive conservatism in reviewing/assessing the ES-15.00S(Q), revision 01 calculations, without benefit of the results of the subsequent detailed study. Dropout setpoint selection at 91.6%*was based on the lowest voltage the 4.16KV motors could be allowed to operate (i.e. 90%) due to voltage drops in the motors' cables and relay inaccuracy considerations.
: 2. Maintaining only two vital buses energized from their operating transformer, if both the corresponding group buses are on their respective Auxiliary Power Transformer (APT) .
--------------
3a. Maintaining three vital buses energized from the operating transformer, if one of the corresponding group buses is transferred to the operating Station Power Transformer (SPT) or 3b. Maintaining three vital buses energized from the operating transformer, if the load which can be transferred from the APTs is reduced by 5 mega volt amps.
----VOLUNTARY LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit l DOCKET NUMBER 5000272 LER NUMBER 93-014-02 PAGE 4 of 4 SIGNIFICANCE:
However, revision 01 to calculation ES-15.00S(Q), "Salem Units 1 and 2 Degraded Grid Study", shows worst case recovery vital bus voltage is 93.2% of 4KV following transfer of the APTs to the SPTs.
A subsequent detailed study shows that the 230 and 460V motors will perform their safety functions with the 91.6% setpoint. As such, the self-imposed administrative controls serve to add greater enhancement to the performance of these motors, from a reliability standpoint.
The initial determination that the 91.6% dropout setpoint did not meet the intent of the UFSAR and the BTP resulted from overly restrictive conservatism in reviewing/assessing the ES-15.00S(Q), revision 01 calculations, without benefit of the results of the subsequent detailed study. Dropout setpoint selection at 91.6%*was based on the lowest voltage the 4.16KV motors could be allowed to operate (i.e.
90%) due to voltage drops in the motors' cables and relay inaccuracy considerations.
 
I~-- -
VOLUNTARY LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station     DOCKET NUMBER     LER NUMBER       PAGE Unit l                          5000272        93-014-02       4 of 4 SIGNIFICANCE:
This report is made for informational purposes, since the dropout setpoint provides adequate protection for the worst case design basis event. As such, this issue is not reportable pursuant the requirements of 10CFR50.73.
This report is made for informational purposes, since the dropout setpoint provides adequate protection for the worst case design basis event. As such, this issue is not reportable pursuant the requirements of 10CFR50.73.
ACTIONS TAKEN/PLANNED:
ACTIONS TAKEN/PLANNED:
Related design changes, including changing the dropout setpoint, were implemented on Unit 1 during its last refueling outage and are scheduled for Unit 2 during its next refueling outage. The self-imposed administrative controls will be maintained for Unit 2 until implementation of the aforementioned design changes. License Change Requests have been submitted to revise Technical Specifications regarding the second level undervoltage relay setpoint.
Related design changes, including changing the dropout setpoint, were implemented on Unit 1 during its last refueling outage and are scheduled for Unit 2 during its next refueling outage.
The importance of adequately considering lower voltage levels whenever evaluating 4KV setpoints for changes has been discussed with the Electrical Engineering Group. Appropriate changes to the UFSAR will be implemented.
The self-imposed administrative controls will be maintained for Unit 2 until implementation of the aforementioned design changes.
License Change Requests have been submitted to revise Technical Specifications regarding the second level undervoltage relay setpoint.
The importance of adequately considering lower voltage levels whenever evaluating 4KV setpoints for changes has been discussed with the Electrical Engineering Group.
Appropriate changes to the UFSAR will be implemented.
Appropriate documents will be revised to incorporate the results of the subsequent study involving the 91.6% dropout setpoint.
Appropriate documents will be revised to incorporate the results of the subsequent study involving the 91.6% dropout setpoint.
MJPJ:pc SORC Mtg. 94-077 ager -tions}}
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tions MJPJ:pc SORC Mtg. 94-077}}

Latest revision as of 05:50, 3 February 2020

LER 93-014-02:on 930722,determine 4 Kv Vital Bus Second Level Undervoltage Protection Dropout Setpoint Would Not Protect Motors.Detailed Study Showed Motors Would Have Performed Intended Safety functions.W/941005 Ltr
ML18101A285
Person / Time
Site: Salem PSEG icon.png
Issue date: 10/05/1994
From: Hagan J, Pastva M
Public Service Enterprise Group
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-014, LER-93-14, NUDOCS 9410200158
Download: ML18101A285 (6)


Text

e OPS~G Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 Salem Generating Station October 5, 1994 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Dear Sir:

SALEM GENERATING STATION LICENSE NO. DPR-70 DOCKET NO. 50-272 UNIT NO. 1 SUPPLEMENTAL LICENSEE EVENT REPORT 93-014-02 This submittal is made to reclassify an occurrence as a Voluntary Report for informational purposes. This occurrence had been previously identified as reportable pursuant to Code of Federal Regulations 10CFR 50.73.

Sincerely yours, MJPJ:pc Distribution

...,nnr.---~

. .~. . v-4 ivu-(;

i I . '.. J..-:

v l11e power is in your hands.

9410200158 941005 PDR ADOCK 05000272 95-2189 REV 7-92 s

N~C FORM 366 .S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COME'LY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LER) COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001 AND TO THE. PAPERWORK REDUCTION PROJECT (31S0-0104), OFFICE OF (See reverse for required number of digits/characters for each block) MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) 05000 272 II PAGE (3)

Salem Generating Station - Unit 1 1 OF 04 TITLE (4) Voluntary Reporting of 4 Kilo-Volt Vital Bus Second Level Undervoltage (UV)

Protection DroJout Setvoint.

EVENT DATE (5) LER NUMBER f6 REPORT NUMBER f7) OTHER FACILITl!':S INVOLVED (8)

I FACILITY NAME DOCKET NUMBER SEQUENTIAL REVISION MONTH DAY YEAR YEAR MONTH DAY' YEAR NUMBER NUMBER Salem Unit 2 05000 311 FACILITY NAME DOCKET. NUMBER

-- -- 05000 07 22 93 93 014 02 .10 05 94 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check one or more (11)

  • MODE (9) 1 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73:71(b)

I L:~E~~~O) I 80 I 20.405(a)(1) 0)

  • 50.36(c)(1) 50. 73 (a)(2)(v) 73.71 (c) 20.405 (a)(1 )(ii) 50.36(c)(2) 50.73(a)(2)(vii) x OTHER 20A05(a)(1)(iii) 50. 73 (a)(2)(i) 50.73(a) (2) (viii) (A) (Specify in Abstract I below and in Text, NRC 20.405(a) (1) (iv) 50.73(a)(2)(ii) 50. 73 (a)(2)(viii)(B) Form 366A) 20.405 (a)(1 )(v) 50.73(a)(2)(iii) 50.73(a)(2)(x) Voluntarv J LICENSEE:CONTACT FOR THIS LER (12).

NAME .. TELEPHONE NUMBER (Include Area Code)

M. J. Pastva, Jr. - LER Coordinator (609) 339-5165 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

REPORTABLE REPORTABLE CAUSE SYSTEM. COMPONENT MANUFACTURER CAUSE SYSTEM COMPONENT MANUFACTURER TONPRDS TO NPRDS SUPPLEMENTAL REPORT EXPECTED 14 EXPECTED MONTH DAY YEAR I YES (If yes, complete EXPECTED SUBMISSION DATE) x NO SUBMISSION DATE (15)

ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)

On 7/22/93, it was determined that the 91. 6% dropout setpoint for second level undervoltage protection of both Salem Units' 4* kilovolt (KV) vital buses would not fully protect the 230 and 460 volt (V) motors should the 4KV bus voltage degrade to less than 93.2%, but greater than 91. 6%. At that time it was concluded the intent of the Updated Final Safety Analysis Report and guidance provided in "Safety Evaluation And Statement Of Staff Positions Relative To The Emergency Power Systems For Operating Reactors" NRC letter, dated 6/2/77, were not fully met. Continued operation of both Sa_lem Uni ts was based upon self-imposed administrative controls on 4KV bus p.lignment until implementation of design changes to change the dropout setpoint. A subsequent detailed study shows the motors would have performed their intended safety functions with the 91. 6% setpoint. As such, this report is made voluntarily for informational purposes.

NRG FORM 366 (5-92)

REQUIRED NUMBER OF DIGITS/CHARACTERS FOR EACH13LOCK BLOCK NUMBER OF TITLE NUMBER DIGITS/CHARACTERS 1 UP TO 46 FACILITY NAME 8 TOTAL 2 DOCKET NUMBER 3 IN ADDITION TO 05000 3 VARIES 'PAGE NUMBER * .

4 UP T076 TITLE 6TOTAL 5 EVENT DATE 2 PER BLOCK 7 TOTAL 2 FOR YEAR 6 LER NUMBER 3 FOR SEQUENTIAL NUMBER 2 FOR REVISION NUMBER 6 TOTAL 7 REPORT DATE 2 PER BLOCK UP TO 18 FACILITY NAME 8 OTHER FACILITIES INVOLVED 8 TOTAL - DOCKET NUMBER 3 IN ADDITION TO 05000 9 1 OPERATING MODE 10 3 POWER LEVEL 1

11 REQUIREMENTS OF 10 CFR CHECK BOX THAT APPLIES UP TO 50 FOR NAME 12 LICENSEE CONTACT 14 FOR TELEPHONE CAUSE VARIES 2 FOR SYSTEM 13 4 FOR COMPONENT EACH COMPONENT FAILURE

' 4 FOR MANUFACTURER NPRDS VARIES 1

14 SUPPLEMENTAL REPORT EXPECTED CHECK BOX THAT APPLIES 6 TOTAL 15 EXPECTED SUBMISSION DATE 2 PER BLOCK

VOLUNTARY LICENSEE EVENT REPORT (LER) TEXT CONTINUATION 1 Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 1 5000272 93-014-02 2 of 4 PLANT AND SYSTEM IDENTIFICATION:

Westinghouse - Pressurized Water Reactor Energy Industry Identification System (EIIS) codes are identified in the text as {xx}

REPORT IDENTIFICATION:

Voluntary Reporting Of 4 Kilo-Volt Vital Bus Second Level Undervoltage (UV) Protection Dropout Setpoint Date of Discovery: 7/22/93 Report Date: 10/5/94 This report was initiated by Incident Report No.93-320.

INITIAL"CONDITIONS:

Unit 1: Mode 1 Reactor Power 80% - Unit Load 815 MWe Unit 2: Mode 1 Reactor Power 100% Unit Load 1140 MWe DISCUSSION:

On July 22, 1993, an initial determination was made that the 91.6%

dropout setpoint for second level undervoltage protection of both Salem Units' 4 kilovolt (KVJ vital buses* {VJ}, would not fully protect the 230 and 460 volt (V) motors should the 4KV bus voltage degrade to less than 93.2%, but greater than 91.6%. At that time it was concluded the intent of the Updated Final Safety Analysis Report

{UFSAR) and guidance provided in "Safety Evaluation And Statement Of Staff Positions Relative To The Emergency Power Systems For Operating Reactors" NRC letter, dated June 2, 1977, were not fully met. This was identified during a self-initiated adequacy review to ensure the intent of the 1977 NRC letter was being met. Continued operation of both sa.lem Units was based upon ensuring that the 4KV bus voltage would be maintained at or above 93.2% by imposition of additional administrative controls on 4KV bus alignment until implementation of design changes to change the dropout setpoint. The NRC was notified of this determination pursuant to 10CFR50.72(b) {l) (ii) (B). In addition, on August 20, 1993, this issue was reported pursuant to the requirements of 10CFR50.73(a) (2) (ii) (B) and 10CFR50.73(a) (2) (v) (D)

A subsequent detailed study shows the motors would have performed their intended safety functions with the 91.6% setpoint. Therefore, a reportable occurrence with the setpoint, as described, does not

..\

VOLUNTARY LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit 1 5000272 93-014-02 3 of 4 DISCUSSION: (cont'd) exist pursuant to 10CFR50.72 or 10CFR50.73.

ANALYSIS:

In July 1993, a self-initiated adequacy review concluded the 91.6% .

dropout setpoint for second level undervoltage protection of both Salem Units' 4 KV vital buses, would not fully protect 230 and 460V motors. Continued operation of both Salem Units was based upon the following self-imposed administrative controls regarding 4KV bus alignment:

1. Hourly logging of 4KV vital bus voltages, maintained between 4.3KV and 4.5KV.
2. Maintaining only two vital buses energized from their operating transformer, if both the corresponding group buses are on their respective Auxiliary Power Transformer (APT) .

3a. Maintaining three vital buses energized from the operating transformer, if one of the corresponding group buses is transferred to the operating Station Power Transformer (SPT) or 3b. Maintaining three vital buses energized from the operating transformer, if the load which can be transferred from the APTs is reduced by 5 mega volt amps.

However, revision 01 to calculation ES-15.00S(Q), "Salem Units 1 and 2 Degraded Grid Study", shows worst case recovery vital bus voltage is 93.2% of 4KV following transfer of the APTs to the SPTs.

A subsequent detailed study shows that the 230 and 460V motors will perform their safety functions with the 91.6% setpoint. As such, the self-imposed administrative controls serve to add greater enhancement to the performance of these motors, from a reliability standpoint.

The initial determination that the 91.6% dropout setpoint did not meet the intent of the UFSAR and the BTP resulted from overly restrictive conservatism in reviewing/assessing the ES-15.00S(Q), revision 01 calculations, without benefit of the results of the subsequent detailed study. Dropout setpoint selection at 91.6%*was based on the lowest voltage the 4.16KV motors could be allowed to operate (i.e.

90%) due to voltage drops in the motors' cables and relay inaccuracy considerations.

I~-- -

VOLUNTARY LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station DOCKET NUMBER LER NUMBER PAGE Unit l 5000272 93-014-02 4 of 4 SIGNIFICANCE:

This report is made for informational purposes, since the dropout setpoint provides adequate protection for the worst case design basis event. As such, this issue is not reportable pursuant the requirements of 10CFR50.73.

ACTIONS TAKEN/PLANNED:

Related design changes, including changing the dropout setpoint, were implemented on Unit 1 during its last refueling outage and are scheduled for Unit 2 during its next refueling outage.

The self-imposed administrative controls will be maintained for Unit 2 until implementation of the aforementioned design changes.

License Change Requests have been submitted to revise Technical Specifications regarding the second level undervoltage relay setpoint.

The importance of adequately considering lower voltage levels whenever evaluating 4KV setpoints for changes has been discussed with the Electrical Engineering Group.

Appropriate changes to the UFSAR will be implemented.

Appropriate documents will be revised to incorporate the results of the subsequent study involving the 91.6% dropout setpoint.

ager -

tions MJPJ:pc SORC Mtg.94-077