ML18152B824

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LER 98-008-00:on 980228,auxiliary Ventilation Fans Were Noted in Condition Outside of Design Basis.Caused by Failure to Recognize Potential Impact of Certain Design Basis Accident Scenarios.No Corrective Actions Needed
ML18152B824
Person / Time
Site: Surry Dominion icon.png
Issue date: 05/22/1998
From: Christian D
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML18152B823 List:
References
LER-98-008, LER-98-8, NUDOCS 9805280237
Download: ML18152B824 (5)
v • d • e


Text

~

, -NRC'F0RM366 (4-95)

.. . --~- .

LICENSEE EVENT REPORT (LER)

.UCLEAR REGULATORY COMMISSION- - ' *

    • " APPROVED BV-c>MB.N0;*3150-0104 EXPIRES 4/30/98 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORY INFORMATION COLLECTION REQUEST: 50.0 HRS
  • REPORTED LESSONS LEARNED ARE INCORPORATED INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY.

FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (T-11 F33), U.S. NUCLEAR REGULATORY COMMISSION, (See reverse for required n_umber of digits/characters for each block) WASHINGTON, DC 20~1, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT WASHINGTON DC~n M FACILITY NAME (1) DOCKET NUMBER (2) PAGE(3)

SURRY POWER STATION, Unit 1 05000 - 280 1 OF5 TITLE (4)

Auxiliarv Ventilation Fans in a Condition Outside Design Basis for Certain Accidents EVENT DATE (5) LER NUMBER (6) 1 REPORT DATE m1 OTHER FACILITIES INVOLVED (8)

SEQUENTIAL REVISION FACILITY NAME DOCUMENT NUMBER MONTH DAY YEAR YEAR MONTH DAY YEAR NUMBER NUMBER Surry Unit 2 05000-281 FACILITY NAME DOCUMENT NUMBER 02 28 98 1998 -- 008 -- 00 05 22 98 05000-OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check one or more) (11)

MODE (9) N 20.2201(b) 20.2203(a)(2)(v) 50. 73(a)(2)(1) 50.73(a)(2)(vlll)

POWER 20.2203(a)(1) 20.2203(a)(3)(i) X 50. 73(a)(2)(ii) 50. 73(a)(2)(x)

LEVEL (10) 100 % 20.2203(a)(2)(1) 20.2203(a)(3)(11) 50. 73(a)(2)(ili) 73.71 20.2203(a)(2)(ii) 20.2203(a)(4) 50. 73(a)(2)(iv) OTHER 20.2203(a)(2)(iii) 50.36(c)(1) 50.73(a)(2)(v) Specify In Abstract below 20.2203(a)(2)(iv) 50.36(c)(2) 50. 73(a)(2)(vii) or In NRC Form 366A LICENSEE CONTACT FOR THIS LER (12 NAME I TELEPHONE NUMBER (Include Area Code)

D. A. Christian, Site Vice President (757) 365-2000 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT {13)

CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE TONPRDS TONPRDS SUPPLEMENTAL REPORT EXPECTED {14) EXPECTED MONTH DAY YEAR I YES (If yes, complete EXPECTED SUBMISSION DATE).

IX I NO SUBMISSION DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)

On February 28, 1998, with Units 1 and 2 at 100% power, Operations personnel identified a potential condition in which the auxiliary ventilation system fans, 1-VS-F-58A and 1-VS-F-588, may be unable to perform their intended safety function. The 1H and 2H busses normally power 1-VS-F-58A and 1-VS-F-588, respectively. The system design also provides for 1-VS-F-58A and 1-VS-F-588 to be powered by their alternate power sources, 2J and 1J busses, respectively. To functionally test this feature requires each fan to be manually aligned to its alternate power source. An Engineering evaluation concluded, that during certain design basis accident scenarios, 1-VS-F-58A and 1-VS-F-588 would not be able to perform their safety function while in this testing configuration. The Station Nuclear Safety and Operating Committee (SNSOC) reviewed the results of the Engir:-ieering ~valuation on April 27, 1998. The SNSOC review concluded, that while compliance with the Technical Specifications has been maintained, the alternate power alignment represented a condition that was outside the design basis of the plant during non-testing periods. To prevent recurrence, measures will be taken that Will ensure that the fans are maintained in a condition that is within the design basis of the plant. This report is being submitted pursuant to 10 CFR 50.73(a)(2)(ii){B}.

9805280237 980522 PDR ADOCK 05000280 S PDR '"'

. * ', \ .- * :* '; ** I * ~ <j*;, , , *.

.'s. i*..iu6i..EARREGULATORY COMMISSION 0

NRC FORM 366A (4-95)

LICENSEE EVENT REPORT (LER)

  • TEXT CONTINUATION FACILITY NAME (1) DOCKET LER NUMBER (6) PAGE (3)

YEAR SEQUENTIAL REVISION NUMBER NUMBER Surry Power Station Unit 1 05000 - 280 1998 -- 008 -- 00 2 OF 5 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

1.0 DESCRIPTION

OF THE EVENT On February 28, 1998, with Units 1 and 2 at 100% power, Operations personnel identified a potential condition in which the auxiliary ventilation system fans [EIIS-VF,FAN],

1-VS-F-58A and 1-VS-F-588, may be unable to perform their intended safety function:

The potential condition is described below.

  • The 1H and 2H busses [EIIS-EB,BU] normally power 1-VS-F-58A and 1-VS-F-588, respectively. The system design also provides for 1-VS-F-58A and 1-VS-F-588 to be powered py their alternate power sources, 2J and 1J busses, respectively. The alternate power capability enables both fans to be supplied power in the event of an extended outage of Emergency Diesel Generators (EDG) No. 1 or No. 2 [EIIS-EK,DG].

~

1J

~ j 2J Normal Power Alignment Alternate Power

.;  :. Alignment

--...._ Swapover Junction Box (Typical)

SBA 58B Figure 1 The alternate power capability is tested each refueling outage in conjunction with the performance of logic testing. To functionally test this feature requires the fan that is normally powered by the non-outage unit's "H" buss to be manually aligned (i.e., by re-terminating the fan motor power cables [E11S-VF,CBL4] at the swapover junction box) to its alternate power source as depicted in Figure 2. An Engineering evaluation concluded, that during certain design basis accident scenarios, 1-VS-F-58A and 1-VS-F-588 would not be able to perform their safety function while in. this testing configuration. Specifically, both fans could become unavailable in the event of a loss of coolant accident (LOCA) coincident with a loss of offsite power (LOOP) and a single equipment failure (e.g., fan).

NRC FORM 366A (4-95)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

  • TEXT CONTINUATION FACILITY NAME (1) DOCKET LER NUMBER (6) PAGE (3)

YEAR SEQUENTIAL REVISION NUMBER NUMBER Sur Power Station Unit 1 05000 - 280 1998 -- 008 - 00 3 OF 5 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

1.0 DESCRIPTION

OF THE EVENT (Continued)

A LOOP/LOCA/single failure scenario and the potential impact on 1-VS-F-58A and 1-VS-F-588 is described in Figures 2 and 3 below.

~

1J 2J

~-

2H
  • Power 1J

.......... .....__. 2J Swapover ----- Swapover

. NoPower JuncUon Box (Typical)

JuncUon Box (Typical) @)

588 .

SBA 58B SBA Pre-Accident Condition Post-Accident Condition

  • Unit 1 refueling outage
  • Unit 2 online
  • Unit 1 refueling outage
  • 1-VS-F-5SA is powered by the
  • Unit2 LOCA normal 1H buss
  • EOG No.1 providing power to 1H
  • 1-VS-F-SBB is powered by the buss alternate 1J buss (testing
  • EOG No. 2 providing power to 2H configuration) buss
  • EOG No. 3 providing power to (accident uriit) _2J buss
  • .1-VS-F-SBA - failed (assumed single failure)
  • 1-VS-F-58B - no power (aligned to alternate 1J buss)

Figure 2 Figure 3 The Engineering evaluation further concluded that while it is necessary to establish the alternate power alignment for testing purposes, the period of time in the subject alignment should be limited. However, a review of testing records revealed previous instances in which 1-VS-F-58A and 1-VS-F-588 remained aligned to the alternate power source for periods of time in excess of that required for testing.

The results of the Engineering evaluation were presented to the Station Nuclear Safety and Operating Committee (SNSOC) on April 27, 1998. The SNSOC review concluded, that while compliance with the Technical Specifications has been maintained, the alternate power alignment represented a condition that was outside the design basis of the plant during non-testing periods. Therefore, this report is being submitted pursuant to 10 CFR 50.73(a)(2)(ii)(B).

NRC FORM 366A (4-95)

NRC FORM 366A .S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

  • TEXT CONTINUATION FACILITY NAME (1) DOCKET LER NUMBER (6) PAGE (3)

YEAR I SEQUENTIAL NUMBER I REVISION NUMBER Surry Power Station Unit 1 05000-280 1998 -- 008 -- 00 40F5 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) 2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS While a LOCA/LOOP/single failure event has not occurred, conditions have existed that could have resulted in 1-VS-F-58A and 1-VS-F-588 being unable to perform their safety function within the required time period during such an event. However, abnormal procedures have been in place to provide instructions for restoring power to affected equipment (including the subject fans) in the unlikely event of a LOCA/LOOP/single failure scenario. These procedures, in conjunction with the training and knowledge level of the Operations staff, would have enabled at least one of these fans to be placed in service as needed to mitigate the effects of such an accident. Therefore, this event resulted in no significant safety consequences or implications.

3.0 CAUSE This event was caused by a failure to recognize the potential impact of certain design

  • basis accident scenarios when 1-VS-F-58A and 1-VS-F-588 are aligned to their alternate power source. As a result, the subject fans* have previously remained aligned to their alternate power source for periods of time in excess of that required for testing.

4.0 IMMEDIATE CORRECTIVE ACTION(S)

No immediate corrective actions were necessary since 1-VS-F-58A and 1-VS-F-588 were aligned to their normal power sources.

5.0 ADDITIONAL CORRECTIVE ACTIONS Engineering evaluated various design basis accident scenarios and the impact on 1-VS-F-58A or 1-VS-F-588 when aligned to their alternate power source. The evaluation concluded that it is necessary to establish the alternate power alignment to perform a complete functional test. However, the alternate power alignment should be limited only to periods in which the testing is being performed.

6.0 ACTIONS TO PREVENT RECURRENCE Measures _will be taken that will allow 1-VS-F-58A and 1-VS-F-588 to be functionally tested and ensure that the fans are maintained in a condition that is within the design basis of the plant.

NRC FORM 366A (4-95)

NRC FORM 366A .S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1) DOCKET LER NUMBER (6) PAGE (3)

YEAR I SEQUENTIAL NUMBER I REVISION NUMBER Surry Power Station Unit 1 05000 -280 1998 -- 008 -- 00 50F5 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) 7.0 SIMILAR EVENTS None.

8.0 MANUFACTURE~MODELNUMBER Not applicable.

NRC FORM 366A (4-95)

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