05000247/LER-2010-003, Regarding Inoperable Emergency Diesel Generators During Refueling Shutdown Due to Inadvertent Isolation of Service Water Cooling Caused by Failure to Properly Verify the In-Service Cooling Header
| ML101410293 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 05/10/2010 |
| From: | Joseph E Pollock Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 10-003-00 | |
| Download: ML101410293 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat |
| 2472010003R00 - NRC Website | |
text
- Entergy Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 Buchanan, N.Y. 10511-0249 Tel (914) 734-6700 J. E. Pollock Site Vice President NL-10-036 May 10, 2010 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop O-P1-17 Washington, D.C. 20555-0001
SUBJECT:
Licensee Event Report # 2010-003-00, "Inoperable Emergency Diesel Generators During Refueling Shutdown Due to Inadvertent Isolation of Service Water Cooling Caused by Failure to Properly Verify the In-Service Cooling Header" Indian Point Unit No. 2 Docket No. 50-247 DPR-26
Dear Sir or Madam:
Pursuant to 10 CFR 50.73(a)(1), Entergy Nuclear Operations Inc. (ENO) hereby provides Licensee Event Report (LER) 2010-003-00. The attached LER identifies an event which is reportable as a safety system functional failure under 10 CFR 50.73(a)(2)(v). This condition was recorded in the Entergy Corrective Action Program as Condition Report CR-IP2-2010-01367.
There are no new commitments identified in this letter. Should you have any questions regarding this submittal, please contact Mr. Robert Walpole, Manager, Licensing at (914) 734-6710.
SicrelyA JEP/cbr cc:
Mr. Samuel J Collins, Regional Administrator, NRC Region I NRC Resident Inspector's Office, Indian Point 3 Mr. Paul Eddy, New York State Public Service Commission LEREvents@inpo.org
Abstract
On March 13, 2010, during a refueling outage work window protective tagout (PTO) of a service water (SW) header valve, the Balance of Plant (BOP) work window manager approved a PTO which authorized closure of a SW valve isolating SW to all three emergency diesel generators (EDG) from the SW 1-2-3 header.
Upon closure of the SW valve, the control room (CR) received a EDG SW low flow alarm and directed the field operator to remove the PTO and un-isolate the header.
The apparent cause was improper verification techniques by the BOP work window manager to determine current plant conditions.
A contributing cause was the field operator did not verify that the actual valve line-up supported the expectation for current plant conditions.
Prior to authorizing work, the BOP window manager checked the unit log for the scheduled swap of SW to header 4-5-6 and then authorized the PTO.
Prior to SW isolation from the 1-2-3 header the field operator failed to verify that the SW 4-5-6 header was in-service.
Corrective actions included coaching the BOP window manager on use.of reliable sources for determining plant condition and the need for good communications with watch personnel, an operations stand down was performed to re-enforce management expectations on properly verifying plant conditions required for PTOs and understanding their impacts prior to implementation.
An Outage Lessons Learned will be prepared to establish a method for implementation during outages that requires peer checking initial conditions for PTO's prepared for specific plant conditions.
A review will be performed to determine if changes to tagging procedures or fleet practices are warranted.
The event had no significant effect on public health and safety.
(If more space is required, use additional copies of NRC Form 366A) (17)
Note:
The Energy Industry Identification System Codes are identified within the brackets {0.
DESCRIPTION OF EVENT
On March 13, 2010, at 18:25 hours, with the plant in cold shutdown preparing for a refueling outage, Technical Specification (TS) 3.8.2 (Electrical Power Systems AC Sources-Shutdown) Condition B was entered for one or more emergency diesel generators (EDG)
{EK} inoperable.
TS 3.8.2 Condition.B was entered due to the isolation of service water (SW)
{BI} header 1-2-3 which provides SW to all three emergency diesel generators (EDG).
TS 3.8.2 required actions B.2.1, B.2.2 and B.2.3 were met as no core alterations were in progress, no movement of recently irradiated fuel was in progress, no dilution was in progress and Shutdown Margin (SDM) was maintained.
TS 3.8.2 required action B.2.4 was immediately commenced to restore SW to the EDGs.
At 18:28
- hours, SW header valve SWN-30 {ISV} was re-opened restoring SW to the EDGs and TS 3.8.2 Limiting Condition for Operation (LCO) met.
The event was recorded in the Indian Point Energy Center Corrective Action Program (CAP) as CR-IP2-2010-01367.
On March 13, 2010, during a refueling outage work window protective tagout (PTO) associated with a service water (SW) header valve, the Balance of Plant (BOP) work window manager approved a PTO which authorized closure of SW valve SWN-30 isolating SW to all three emergency diesel generators (EDG) from the SW 1-2-3 header.
Upon closure of valve SWN-30, the control room (CR) received an EDG SW low flow trouble alarm.
The CR contacted the field operator and was notified that valve SWN-30 providing SW supply to all three EDGs was closed during application of a PTO for the 1-2-3 SW header.
The CR operator directed the field operator to remove the PTO and open SWN-30.
SW was isolated to the EDGs for approximately 3 minutes.
Investigation determined that during outage work preparations, PTO SW-025-SSWN-61-2 was prepared to open, inspect and repack valve SWN-62-1.
Valve SWN-62-1 is a SW isolation valve for the 21 EDG associated with the 1-2-3 SW header.
The PTO was approved and released to the field to be hung.
The PTO required the 4-5-6 SW header to be in-service because the PTO required valve SWN-30 to be closed which isolates SW to the EDGs from the 1-2-3 SW header.
The BOP work window manager knew that the 1-2-3 SW header was scheduled to be swapped to the 4-5-6 header on his day off.
Upon returning to work the BOP work window manager checked the unit log for entry of the SW header swap and noted the entry recorded a swap to the 4-5-6 header.
Based on unit log entry, the BOP work window manager authorized hanging the PTO.
The BOP work window manager did not verify with on-watch personnel the status of the SW header prior to authorizing the PTO.
During the pre job brief the BOP work window manager informed the field operator that the 4-5-6 SW header was in service.
The field operator went to the field and hung the PTO and closed valve SWN-30 which was then peer checked.
The field operator did not verify that the 4-5-6 SW header was in-service prior to closing valve SWN-30 although the two SW header isolation valves are adjacent to each other.
The Cause of Event The apparent cause for isolation of SW to the EDGs was the BOP work window manager used improper verification techniques to determine the current plant conditions.
A contributing cause was the field operator did not verify that the actual valve line-up supported the expectation for the actual plant condition.(9-2007)
LICENSEE EVENT REPORT (LER)
FACILITY NAME (1)
DOCKET (2)
LER NUMBER (6)
PAGE.(3)
SEQUENTIAL REVISION YEAR NUMBER NUMBER Indian Point Unit 2 05000-247 2010 003 00 3
OF 3
Corrective Actions
The following corrective actions have been or will be performed under Entergy's Corrective Action Program to address the cause and prevent recurrence:
- The BOP window manager was coached on use of reliable sources for determining plant condition and the need for good communications with watch personnel.
" An operations stand down was performed to re-enforce management expectations on properly verifying plant conditions required for PTOs and understanding their impacts prior to implementation.
- An Outage Lessons Learned will be prepared to establish a method for implementation during outages that requires peer checking initial conditions for PTO's prepared for specific plant conditions.
" A review will be performed to determine if changes to tagging procedures or fleet practices are warranted.
Event Analysis
The event is reportable under 10CFR50.73(a) (2) (v) (B)and (D) [Any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to: (B) Remove residual heat (D) Mitigate the consequences of an accident].
On March 13, 2010, at approximately 18:25 hours, operations entered TS 3.8.2 Condition B for one or more required EDGS inoperable due to isolation of the SW header supplying SW to all three EDGS.
At 18:28 hours, the SW header isolation valve SWN-30 was opened restoring SW supply to the EDGs.
Operations determined the condition was a safety system functional failure and provided an 8-hour non-emergency notification to the NRC (EN#45765) at approximately 21:38 hours.
TS 3.8.2.b requires two EDGs capable of supplying two safeguards trains of the onsite AC electric power distribution subsystems required by TS 3.8.10.
The actions for TS 3.8.2 Condition B, One or more required EDGs inoperable, requires (B.1) Declaring the affected required feature with no EDG available inoperable immediately OR (B.2.1) suspend core alterations immediately, and (B.2.2) suspend movement of recently irradiated fuel assembles immediately, and (B.2.3) suspend operations involving positive reactivity additions that could result in loss of required SDM or boron concentration immediately, and (B.2.4) initiate action to restore required EDGs to operable status immediately.
The inoperable condition was corrected within approximately three minutes by restoring SW cooling to the EDGs.
The plant was in cold shutdown with no core alteration or dilution in progress and SDM was maintained.
TS 3.8.2 LCO was met following completion of the required actions restoring SW'cooling to the EDGs.
Past Similar Events A review was performed of the past three years of Licensee Event Reports (LERs) for events that involved a SSFF due to inoperable equipment as a result of inadvertent equipment operation.
No LERs were identified.
Safety Significance
This event had no significant effect on the health and safety of the public.
There were no actual safety consequences for the event because there were no accidents or transients requiring the EDGs.
An evaluation was performed of EDG operation, if required to start and operate as a result of a loss of offsite power (LOOP),
with SW isolated to the EDGs (engine jacket water coolers and lube oil coolers) at full rated load (1750 kW) and maximum Mode 5 loads (1215 kW).
The evaluation determined the EDGs could operate without SW for the duration of this event and perform their required function.
There are CR and local trouble alarms to alert operators of problems with EDGs and their cooling water and plant procedures to identify and address problems.