05000251/LER-2008-002, Safety Injection Isolated in Mode 3 Due to Inadequate Configuration Control
| ML081960085 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 07/02/2008 |
| From: | Jefferson W Florida Power & Light Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-2008-146 LER 08-002-00 | |
| Download: ML081960085 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown |
| 2512008002R00 - NRC Website | |
text
FPL 10 CFR § 50.73 L-2008-146 JUL
- - 2 2008 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555-00001 Re:
Turkey Point Unit 4 Docket No. 50-251 Reportable Event: 2008-002-00 Date of Event: May 5, 2008 Safety Injection Isolated in Mode 3 Due to Inadequate Configuration Control The attached Licensee Event Report 05000251/2008-002-00 is being submitted pursuant to 10 CFR 50.73(a)(2)(i)(B) and 10 CFR 50.73(a)(2)(v)(D) to provide notification of the subject event.
If there are any questions, please call Ms. Olga Hanek at 305-246-6607.
Very truly yours, William Jefferkri, Jr.
Vice President Turkey Point Nuclear Plant Attachment cc:
Regional Administrator, USNRC, Region II Senior Resident Inspector, USNRC, Turkey Point Nuclear Plant kW1~
an FPL Group company
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/201T
- 9-2007)
Estimated burden per response to comply with this mandatory collection request: 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the Records and FOIA/Privacy Service Branch (T-5 LICENSEE EVENT REPORT (LER)
F52), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to infocollects@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
I3.
PAGE Turkey Point Unit 4 05000251
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1 of 6
- 4. TITLE Safety Injection Isolated in Mode 3 Due to Inadequate Configuration Control
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MOT A
EA FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR I
NUMBER NO.
IFACILITY NAME DOCKET NUMBER 5
5 2008 2008-002 - 00 7
2 2008
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
[E 20.2201(b)
[I 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
[I 50.73(a)(2)(vii) 3 0 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
[1 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
[I 50.73(a)(2)(viii)(B)
El 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL El 20.2203(a)(2)(ii)
[I 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4)
El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71(a)(5) 0 El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
[E OTHER El 20.2203(a)(2)(vi) 0 50.73(a)(2)(i)(B)
[
50.73(a)(2)(v)(D)
Specify in Abstract below or in a) Low pressurizer [EIIS: AC, PZR] pressure.
b) High containment [EIIS: NH] pressure.
c) Steam line differential pressure two out of three per loop (between steam line and main steam [EIIS: SB]
header).
d) High steam flow in one out of two per steam line (2/3 lines) with low Tavg (2/3) or low steam line pressure (2/3).
e) Manual actuation.
The principal components of the SI System which provide emergency core cooling immediately following a loss of coolant are the accumulators (one for each loop), the four SI (high head) pumps and the two RHR (low head) pumps. The accumulators, which are passive components, discharge into the cold legs of the reactor coolant piping when pressure decreases to approximately 660 psig, thus rapidly assuring core cooling for large breaks. They are located inside the containment.
The safety injection signal opens the SI System isolation valves and starts the SI pumps and the RHR pumps. The SI pumps take suction from the refueling water storage tank and all four are aligned to provide core cooling to both Units 3 and 4.
The RHR pumps deliver to all three cold legs through the piping between the accumulators and the cold legs. The SI pumps deliver into two separate headers one going to the cold legs and one to the hot legs.
The valves which control the two flow paths to the hot legs are maintained inoperative by keeping the motor circuit breakers locked open at the motor control centers. The header to the cold legs divides into three injection lines connecting to the pipes from the accumulators close to the RCS cold leg piping. Valve 4-867 is located in the common header and is required to be locked open and backseated.
Sequence of Events On April 30, 2008, Operations personnel were performing actions to realign Unit 4 SI cold leg injection from a clearance zone (63-62) which supported SI System alignment for Safeguards Testing. This restoration was being performed in accordance with procedure 4-OSP-203. 1, Train A Engineered Safeguards Integrated Test, Attachment 16.
At approximately 0346 on April 30, a part of the restoration process included removal of the caution tag from manual valve 4-867. The caution tag did not specify the required restoration (correct or normal) position for the valve when the tag was removed. The only alignment information on the caution tag was "Tag Hung." The personnel removing the tag expected valve 4-867 would be correctly positioned during a subsequent alignment process as unit startup continued.
A unit startup was in progress in accordance with procedure 4-GOP-503, Cold Shutdown to Hot Standby.
On May 4, 2008 at approximately 0600, Unit 4 entered Mode 4 (reactor coolant average temperature greater than 200 degrees F). At this time, SI was not in proper alignment as required by 4-GOP-503. Also, the Shift Manager signed for completion of the SI System alignment, but it had not been properly completed.
SION
On May 5, 2008, at approximately 0741, Unit 4 reactor coolant temperature exceeded 380 degrees F. At this time, Unit 4 was in noncompliance with TS LCO 3.5.2.a due to manual valve 4-867 being locked closed instead of the required locked open and backseated.
On May 5, 2008, at approximately 1237 procedure 4-OSP-202.1, Safety Injection/Residual Heat Removal Flowpath Verification, was being performed by Engineering as directed by 4-GOP-503, step 5.30 for SI flow path verification. During the verification, it was discovered that SI boundary isolation valve 4-867 was locked closed. At the time of discovery, Unit 4 was in day 37 of a refueling outage, in Mode 3 above 380 degrees F. The required position of this valve for the then-current plant condition was locked open and backseated. Unit 4 entered TS 3.0.3 because the cold leg injection flow path was isolated.
At approximately 1307, manual valve 4-867 was placed in its correct alignment (locked open and backseated) and Unit 4 exited TS 3.0.3. Unit 4 had been in TS 3.0.3 for 30 minutes.
Analysis Release of clearance zone 63-62 did not specify valve 4-867 to be locked open and backseated. Safeguards procedure release did not adequately realign valve 4-867. The safeguards test procedure 4-OSP-203.1 and OSP-203.2, Attachment 16 directs the operator to align per procedure 4-OP-20 1, Filling/Draining the Refueling Cavity and the SFP Transfer Canal, Attachment 1 or 8, neither of which include valve 4-867.
SI System alignment procedure for Mode 4 entry was not properly completed (Procedure 4-GOP-503, step 3.1.1.15). The Shift Manager signed that the valve alignment had been completed following statement to that effect by the Outage Control Center Coordinator (a previously SRO-licensed individual). However, the alignment had not been completed.
Reportability
SI pump discharge-to-cold leg injection isolation valve 4-867 was discovered out of position while Unit 4 was in Mode 3. Valve 4-867 is required to be locked open and backseated when RCS temperature is greater than 380 degrees F in accordance with the double asterisk note for the Mode 3 applicability of TS LCO 3.5.2. Unit 4 was in TS 3.0.3 as the required injection flow path to the RCS cold legs for all SI pumps was unavailable for approximately 30 minutes from time of discovery at 1237 until correction at 1307. The valve was out if its required position for approximately 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 26 minutes, from 0741 when RCS temperature was above 380 degrees F until the valve was repositioned at 1307.
An eight-hour report was made to the NRC Operations Center in accordance with 10 CFR 50.72(b)(3)(v)(D) for a condition that at the time of discovery could have prevented the fulfillment of the safety function of a system needed to mitigate the consequences of an accident (Safety Injection) since all four SI pumps would not have been able to provide coolant makeup to the RCS cold legs to mitigate a LOCA. The condition is also required to be reported in writing to the NRC within 60 days of discovery in accordance with 10 CFR 50.73(a)(2)(v)(D) (prevented fulfillment of safety function), and 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by the TSs. The condition is reportable under 10 CFR
50.73(a)(2)(i)(B) since TS LCO 3.5.2.a was not met, there is no required action addressing the condition and the condition existed for greater than the one hour required by TS 3.0.3 to initiate a plant shutdown.
ANALYSIS OF SAFETY SIGNIFICANCE The ICCDP (Incremental Conditional Core Damage Probability) for having the 4-867 valve closed for 5.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> is 7.6E-08. The main reason for the relatively low risk significance is the proceduralized action to use the alternate path available - the hot leg injection line.
The ICCDP calculated above is conservative for the following reasons:
- 1. At the time of the event, the unit was in Mode 3 at a reduced decay heat level after a refueling outage.
In the PRA model, it is assumed that the unit is in Mode 1 and has been for some time, i.e., the decay heat level is much greater following a trip. The lower decay heat level allows for more time for recovery actions than assumed in the model.
- 2. In the PRA model, credit for using the alternate (hot leg) injection path is only taken for "small-small" LOCAs (3/8 inch to 2 inch diameter). It is very likely that there is enough time for the operators to use the alternate injection path for the larger "small" and "medium" LOCAs as well.
CORRECTIVE ACTIONS
Corrective actions include the following:
- 1. Revise General Operating Procedures (GOP) to ensure mitigating system flowpath verification surveillances are included, can not be waived during refueling outages and are completed prior to SM holdpoints (e.g., Mode 5 to 4 escalating, Mode 4 to 3 and Mode 3 greater than 380 degrees).
- 2. Determine the safety significant systems that cannot be waived and are required to have a valve alignment performed prior to Mode changes when returning from a refueling outage, and revise the GOPs to incorporate this list.
- 3. Revise the SM hold points in the GOPs to include specific information that ensures the Mode 5 and Mode 6 signatures verify all requirements are met for mode escalation.
- 4. Add to the appropriate procedure guidance and expectations that identify the standards for configuration control processes. This would include the standards for signing off completed alignments in the GOP series of procedures.
- 5. Ensure the safeguards test procedures direct the operator to align components without interpretation following clearance restorations.
ON
ADDITIONAL INFORMATION
EIBS Codes are shown in the format [EIIS SYSTEM: IEEE system identifier, component function identifier, second component function identifier (if appropriate)].
FAILED COMPONENTS IDENTIFIED:
PREVIOUS SIMILAR EVENTS