IR 05000335/1998013
| ML17229A908 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 11/06/1998 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML17229A907 | List: |
| References | |
| 50-335-98-13, 50-389-98-13, IEIN-96-048, IEIN-96-48, NUDOCS 9811190173 | |
| Download: ML17229A908 (8) | |
Text
U.S. NUCLEAR REGULATORY COMMISSION
REGION II
Docket Nos:
License Nos:
50-335, 50-389 DPR-67, NPF-16 Report Nos:
50-335/98-13, 50-389/98-13 Licensee:
Florida Power & Light Co.
Facility:.
St. Lucie Nuclear Plant, Units 1 8 2 Location:
6351 South Ocean Drive Jensen Beach, FL 34957 Dates:
October 21 - 31, 1998 Inspectors:
Approved by:
T. Ross, Senior Resident Inspector D. Lanyi, Resident Inspector S. Ninh, Project Engineer L. Wert, Chief Reactor Projects Branch 3 Division of Reactor Projects Enclosure, 9811190173 981.106 PDR ADOCK 05000335
EXECUTIVE SUMMARY't.
Lucie Nuclear Plant, Units 1 &. 2 NRC Inspection Report 50-335/98-13, 50-389/98-13 This special inspection report included a review of the licensee's actions and technical evaluations associated with inoperability of the Unit 2 power operated relief valve (PORV) block valves due to a recently promulgated revision in Motor Operated Valve (MOV) methodology.
~En ineerin
~
Site Engineering's response to the motor-operated valve performance issues described in Information Notice 96-48, Supplement 1, was prompt and aggressive.
Technical evaluations were timely and of good quality. Information provided by the licensee indicated that both Unit 2 PORV block valves were inoperable from approximately 1993 until identification of the issues on August 7, 1998, and the TS required action was not taken. The licensee determined that the valves may not have closed under certain conditions.
Upon identification, compliance with Technical Specifications (TS) and reportability requirements, and implementation of interim corrective actions were appropriate.
After review of this issue, the NRC concluded that while a violation did occur, enforcement discretion is warranted and issuance of a Notice is not appropriate in this cas E2
, E2.1 Engineering Support of Facilities and Equipment Motor-0 crated Valve Performance Issues Ins ection Sco e (92901) (37551)
b.
The inspector reviewed the licensee's actions and technical evaluations associated with motor operated valve analysis methodology following issuance of Information Notice (IN) 96-48, Supplement 1, "Motor-Operated Valve Performance Issues," dated July 24, 1998.
Observations and Findin s In light of recent tests and studies of motor-actuator output, Limitorque retracted its relaxation of sizing criteria for ac-powered motor actuators through issuance of Limitorque Technical Update (TU) 98-01.
NRC IN 96-48, Supplement'1, disseminated this information to the industry. Recognizing the significance of the issues identified by IN 96-48, Supplement 1, the licensee's engineering department initiated a prompt, thorough review of all affected motor-operated valves (MOV)for Unit 1 and Unit 2. Specific Site Engineering personnel were dedicated to the project and worked through the weekend.
On August 7, the licensee identified several MOVs that had insufficient torque margins to accommodate the additional conservatism specified in IN 96-48, Supplement 1. Of these, only the Unit 2 Power Operated Relief Valve (PORV)
Block Valves involved Technical Specification (TS) operability concerns.
I After declaring the PORV block valves inoperable, the licensee entered TS Action 3.4.4.a., "With one or more block valve(s) inoperable, within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> either restore the block valve(s) to operable status or close the block valve(s) and remove power from the block valve(s); otherwise, be in at least hot standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />." The licensee promptly complied with the action statement by ensuring both block valves were closed and de-energized.
Within the next two weeks, a temporary system alteration (TSA) was installed to restore operability of both PORV block valves, and to reopen one of them. Also, permanent repair plans were incorporated into the upcoming Unit 2 outage.
Furthermore, Licensee Event Report (LER) 50-389/98-005 (see section E8.1) was submitted to document the problem in accordance with 10 CFR 50.73 and describes that the past inoperability of the PORV block valves exceeded the Action time allowed by TS.
The inspectors verified the licensee's immediate corrective actions complied with TS 3.4.4.a and followed up on the TSA efforts to restore interim operability. The licensee's safety assessment concluded that the PORV block valve inoperability had not adversely affected public health and safety. The LER also noted that the safety analysis for an inadvertent opening PORV does not credit closing of the block valve to prevent exceeding safety limits. The Final Safety Analysis Report (FSAR) also contains an analysis of inadvertent lifting of both PORVs, which indicates that the core is protected from departure from nucleate boiling conditions by Reactor Protection System actions with no credit for operator actions to close the PORVs or block valves. The inspectors reviewed the assessment, the LER, and applicable sections of the TS and FSAR. The inspectors determined that the conclusions in the safety assessment were supported by the information in the FSAR and T The inspectors also reviewed the associated Condition Report (CR 96-2725-1) for technical adequacy.
The inspector found that the work was thorough and addressed all potentially affected MOVs. Engineering's justification for eliminating a detailed review for most of the MOVs was well documented and appropriate.
The inspectors reviewed the calculations associated with the four MOVs that required a TSA. The TSA consisted of removing the thermal overload devices to reduce the voltage drop across the circuit.
The inspectors concluded that the assumptions made by the engineering staff appeared valid and the results satisfactorily met the licensee's criteria for operability.
Based on the information developed during the inspection, the NRC determined that this issue constitutes a violation of regulatory requirements.
From approximately 1993 until identification on August 7, 1998, both Unit 2 PORV block valves were inoperable and the TS 3.4.4.a required action was not taken.
After review of this violation, the NRC has concluded that while a violation did occur, enforcement discretion in accordance with Section VII.B.3, Old Design Issues, of the Enforcement Policy, is warranted and issuance of a Notice is not appropriate in this case.
The specific bases for the decision to exercise enforcement discretion included:
The licensee promptly identified the issue after a review of vendor information and NRC IN 96-48, Supplement 1, issued July 24, 1998. The inspectors noted that significant effort was expended by engineering personnel addressing the issue.
The licensee promptly completed actions to comply with the TS action upon discovery.
Both valves were closed and power was removed. NRC reviews indicated that the interim and planned corrective actions, including valve actuator modifications, adequately address the deficiency.
The issue is considered an old design issue which was not likely to be identified through routine licensee efforts.
The revision to valve operator analysis factors was recently promulgated by the vendor.
There was a low safety significance associated with the postulated failure of the reactor coolant system's block valves for the powered operated relief valves, as discussed in LER 50-389/98-05.
The common cause ramifications of this postulated failure mechanism were reduced by the licensee normally keeping one of the two block valves closed.
Also, multiple safety systems could mitigate the consequences of the block valves not closing until the differential pressure was reduced allowing the valve(s) to be closed.
This postulated failure did not affect the low temperature over-pressure protection function associated with the powered operated relief and block valves.
The issue was not the direct result of inadequate licensee performance and is not reflective of current licensee performance The deficiency was appropriately reported to the NRC in an informative LE c.
Conclusions Site Engineering's response to the motor-operated valve performance issues described in Information Notice 96-48, Supplement 1, was prompt and aggressive.
Technical evaluations were timely and of good quality. Information provided by the licensee indicated that both Unit 2 PORV block valves were inoperable from approximately 1993 until identification of the issues on August 7, 1998, and the TS required action was not taken. The licensee determined that the valves may not have closed under certain conditions.
Upon identification, compliance with Technical Specifications and reportability requirements, and implementation of interim corrective actions were appropriate.
After review of this issue, the NRC concluded that while a violation did occur, enforcement discretion is warranted and issuance of a Notice is not appropriate in this case.
ES Miscellaneous Engineering Issues (92903)
E8.1 O en LER 50-335/98-005-00; New MOV Methodology Caused Past PORV Block Valve Operability Problems.
The event and corrective actions are discussed in section E2.1. The licensee's submittal of the subject LER met the requirements of 10 CFR 50.73. The corrective actions implemented and planned to be implemented were reasonable to prevent recurrence of the event.
The LER willremain open pending review of final corrective actions.
V. Mana ement Meetin s and Other Areas The inspectors presented the inspection results to members of the licensee's staff on October 30, 1998.
The licensee acknowledged the findings presented.
No proprietary information was identified.
IP 37551:
IP 92901:
IP 92903:
INSPECTION PROCEDURES ~IP USED Onsite Engineering Followup - Plant Operations Followup - Engineering ITEMS OPENED CLOSED AND DISCUSSED OPENED 50-389/98-05 CLOSED LER New MOV Methodology Past PORV Block Valve Operability Problem (Section E8.1)
None
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