05000220/LER-2012-003, Regarding Loss of Isolation Function on Shutdown Cooling System Suction Line Due to an Operating Procedure Deficiency
| ML12355A372 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 12/14/2012 |
| From: | Philippon M Constellation Energy Nuclear Group, EDF Group, Nine Mile Point |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 12-003-00 | |
| Download: ML12355A372 (8) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2202012003R00 - NRC Website | |
text
Michel A. Philippon Plant General Manager P.O. Box 63 Lycoming, New York 13093 315.349.5205 315.349.1321 Fax CENG.
a joint venture of 0Coinwtelationi Energy1J NINE MILE POINT NUCLEAR STATION December 14, 2012 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION:
SUBJECT:
Document Control Desk Nine Mile Point Nuclear Station Unit No. 1; Docket No. 50-220 Licensee Event Report 2012-003, Loss of Isolation Function on Shutdown Cooling System Suction Line due to an Operating Procedure Deficiency In accordance with 10 CFR 50.73(a)(2)(v)(D), please find attached Licensee Event Report 2012-003, Loss of Isolation Function on Shutdown Cooling System Suction Line due to an Operating Procedure Deficiency.
There are no regulatory commitments in this submittal.
Should you have questions regarding the information in this submittal, please contact John J. Dosa, Director Licensing, at (315) 349-5219.
Very truly yours, MAP/DEV
Attachment:
Licensee Event Report 2012-003, Loss of Isolation Function on Shutdown Cooling System Suction Line due to an Operating Procedure Deficiency cc:
Regional Administrator, NRC Project Manager, NRC Resident Inspector, NRC
ýý9 00-P0-
ATTACHMENT LICENSEE EVENT REPORT 2012-003 LOSS OF ISOLATION FUNCTION ON SHUTDOWN COOLING SYSTEM SUCTION LINE DUE TO AN OPERATING PROCEDURE DEFICIENCY Nine Mile Point Nuclear Station, LLC December 14, 2012
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Nine Mile Point Unit 1 05000220I 1 OF 6
- 4. TITLE Loss of Isolation Function on Shutdown Cooling System Suction Line due to an Operating Procedure Deficiency
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED FACILITY NAME DOCKET NUMBER SEQUENTIAL REV MONTH DAY YEAR YEAR NUMBER NO.
None NA FACILITY NAME DOCKET NUMBER 10 18 2012 2012 003 00 12 14 2012 None NA
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMIrTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
[E 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii)
--N El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
- 10. POWER LEVEL E] 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)
El 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
[E 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
[I 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4) 100 El 20.2203(a)(2)(iv)
[1 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71(a)(5)
El 20.2203(a)(2)(v)
[I 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
[E OTHER El 20.2203(a)(2)(vi)
[E 50.73(a)(2)(i)(B)
[
50.73(a)(2)(v)(D)
Specify in Abstract below or in C. INOPERABLE STRUCTURES, COMPONENTS, OR SYSTEMS THAT CONTRIBUTED TO THE EVENT:
Both of the SDC system suction line isolation valves (IV 38-01 and IV 38-02) were open and de-energized, thereby rendering their isolation function inoperable. There were no other inoperable structures, systems, or components that contributed to the event.
D. DATES AND APPROXIMATE TIMES OF MAJOR OCCURRENCES
Sept. 20, 2012
@ 09:23 Sept. 20, 2012
@ 19:25 Sept. 21, 2012
@ 00:52 Sept. 22, 2012
@ 09:45 Oct. 18, 2012
@ 13:00 NMP1 scrams on low reactor water level (addressed in a separate LER).
Cold shutdown conditions are achieved.
Both SDC suction line isolation valves (IV 38-01 and IV 38-02) are de-energized in the open position.
Power to both IV 38-01 and IV 38-02 is restored, and the valves are declared operable.
It is determined that operation with both SDC suction line isolation valves open and de-energized is a reportable condition in accordance with 10 CFR 50.73(a)(2)(v)(D). Condition Report CR-2012-009540 initiated.
E. OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED
None
F. METHOD OF DISCOVERY
The determination that SDC system operation with both suction line isolation valves open and de-energized was a reportable condition was made as a result of discussions of the condition and associated reportability criteria between Operations and Licensing staff members and management following the September 2012 NMP1 forced outage.
G. MAJOR OPERATOR ACTION:
None. No operational conditions requiring operator action occurred as a result of the determination that SDC system operation with both suction line isolation valves open and de-energized was a reportable condition.
NRC FORM 366 (10-2010)
H. SAFETY SYSTEM RESPONSES:
None. No operational conditions requiring the response of safety systems occurred as a result of this event.
I1. CAUSE OF EVENT:
In March 2009, the SDC system operating procedure was revised to add instructions for defeating and restoring the SDC system isolation function. The purpose of these changes was to enhance nuclear safety by preventing inadvertent or spurious closure of the isolation valves and the resultant interruption of the shutdown cooling decay heat removal function by de-energizing the valves in the open position. The procedure was determined to be in accordance with the requirements of TS Section 3.2.7.f, which allows continued operation with both of the SDC system suction line isolation valves inoperable provided there are no operations with a potential for draining the reactor vessel (OPDRV). As explained in the Bases for TS Section 3.2.7, operation with the SDC system in service is not considered an OPDRV so long as system integrity is maintained, meaning that the SDC piping is intact and no maintenance is being performed that has the potential for draining the reactor vessel through the SDC system. What was not recognized was that implementation of the procedure change allowed placing the system in a configuration that resulted in a reportable condition. Since 2009, the procedure has been periodically implemented during outage periods.
The apparent cause of having a procedure initially put into place that, when implemented, resulted in a reportable condition is that Operations personnel involved in the procedure development did not recognize the need for, or coordinate, reviews from other key station stakeholders. There was a mindset by those involved that since the condition was permitted by TS and enhanced nuclear safety (from a preservation of decay heat removal perspective), the procedure change was acceptable. As a result, no cross-disciplinary reviews of the procedure change were performed by other station stakeholders. A contributing cause is that training on the requirements of 10 CFR 50.72 and 10 CFR 50.73 did not adequately prepare Operations personnel to recognize the reportable condition.
This event was entered into the Nine Mile Point Nuclear Station corrective action program as condition report number CR-2012-009540.
II1. ANALYSIS OF THE EVENT:
The SDC system suction line isolation valves perform both a reactor coolant system isolation function and a primary containment isolation function. The purpose of this function during shutdown conditions is to isolate the SDC system from the reactor coolant system to mitigate the loss of reactor coolant inventory in the event of a leak that breaches the SDC system boundary. A loss of reactor coolant inventory could lead to a loss of decay heat removal for fuel in the reactor pressure NRC FORM 366 (10-2010)
vessel. The loss of the isolation function is reportable in accordance with 10 CFR 50.73(a)(2)(v)(D) as an event or condition that could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident.
There were no actual safety consequences associated with this condition. Reactor vessel low-low water level initiates the automatic closure of the SDC isolation valves. NMP1 did not experience any conditions that would have required the SDC system to be isolated to preserve reactor coolant system inventory. Additionally, the NMP1 SDC system is a closed loop system with the sole purpose of removing decay heat absorbed by the reactor water during shutdown conditions. Unlike later vintage boiling water reactors, the NMP1 SDC system does not have multiple operating modes or cross-connections to other systems. As a result, the NMP1 SDC system is not subject to system misalignments that could cause a reactor coolant inventory reduction event. Based on these considerations, it is concluded that the safety significance of this event is low and the event did not pose a threat to the health and safety of the public or plant personnel.
This event affects the NRC Reactor Oversight Process (ROP) Performance Indicator (PI) for Safety System Functional Failures (SSFF) because the event could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident. There were three instances of this SSFF in the last four calendar quarters, occurring during the September 2012, July 2012, and February 2012 forced outages. The NRC performance indicator for SSFF is projected to rise from 0 to 3 at the end of the fourth quarter 2012. The threshold from Green to White for this P1 is 6, and the PI will remain green.
IV. CORRECTIVE ACTIONS
A. ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:
The SDC system operating procedure has been revised to remove the section that contained the instructions for defeating and restoring the SDC system isolation function.
B. ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:
Additional licensed operator training will be conducted regarding application of the reportability criteria of 10 CFR 50.72 and 10 CFR 50.73, with an emphasis on events or conditions that could prevent fulfillment of a safety function (10 CFR 50.72(b)(3)(v) and 10 CFR 50.73(a)(2)(v)).
V. ADDITIONAL INFORMATION
A. FAILED COMPONENTS:
There were no failed components that contributed to this event.
B. PREVIOUS LERs ON SIMILAR EVENTS:
None NRC FORM 366 (10-2010)
C. THE ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) COMPONENT FUNCTION IDENTIFIER AND SYSTEM NAME OF EACH COMPONENT OR SYSTEM REFERRED TO IN THIS LER:
COMPONENT Shutdown Cooling System Isolation Valve D. SPECIAL COMMENTS:
None IEEE 803 COMPONENT IDENTIFIER N/A ISV IEEE 805 SYSTEM IDENTIFICATION BO BO NRC FORM 366 (10-2010)