L-2013-217, Revised Technical Specification Special Report, Failure of Channel a Reactor Vessel Level Monitoring System (Rvlms) on June 4, 2013

Revised Technical Specification Special Report, Failure of Channel a Reactor Vessel Level Monitoring System (Rvlms) on June 4, 2013

ML13205A168
Person / Time
Site:	Saint Lucie
Issue date:	07/03/2013
From:	Katzman E Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2013-217
Download: ML13205A168 (3)

Text

0FPL. July 3, 2013 L-2013-217 10 CFR 50.36 U. S. Nuclear Regulatory Commission Attn:' Document Control Desk Washington, D. C. 20555 Re: St. Lucie Unit 2 Docket No. 50-389 Date bf Event: June 4, 2013 Revised Technical Specification Special Report Failure of Channel "A" Reactor Vessel Level Monitoring System (RVLMS)

This report revises FPL letter L-2013-215 in its entirety. The date was inadvertently omitted from the cover page. The attachment remains unchanged and is being submitted pursuant to the reqiiirrnIents of St. Lucie Unit 2 Technical Specification 3.3.3.6, Action d.2, Table 3.3-10, and Technical Specification 6.9.2. This report provides notification that one channel of the Reactor Vessel Level Monitoring System (RVLMS) is out of service for greater then 30 days. This report includes the cause and what the corrective actions will be to restore the inoperative channel.

Please contact us if there any questions regarding this information.

Sincerely', -

Eric S. Katzman Licensing Manager St. Lucie Plant ESK/dIc Attachment Florida Power & Ught Company -

6501 S. Ocean Drive, Jensen Beach, FL 34957

St. Lucie Unit 2 L-2013-217 Docket No. 50-389 Attachment Page I of 2 I. TITLE Failure of the Unit # 2 Channel "A" Reactor Vessel Level Monitoring System (RVLMS) probe.

I1. EVENT DESCRIPTION On June 4, 2013, St. Lucie Unit # 2 was in Mode I at 100% power. Operations reported that the RVLMS "A" Channel, Sensor #1 Heated Junction Thermocouple (HJTC) failed due to inconsistent readings. The degraded condition of Sensor # 1 on the "A" Channel forced the site into T.S. 3.3.3.6. (See Below)

Each RVLMS channel consists of a probe that uses eight heated junction thermocouple sensors and reactor vessel level is calculated from the HJTC temperature outputs at the eight sensor levels in the reactor vessel. The requirement of T.S. 3.3.3.6 requires a minimum of four out of the eight sensors per channel operable for Modes 1, 2 and 3. Four sensors were out of service, when the fifth HJTC sensor failed on June 4 th 2013.

III. CAUSE OF THE EVENT The cause of the failed HJTC sensors was determined to be poor connections on the reactor vessel head area. The cause was identified by the performance of Time Domain Testing and CHAR testing.

IV. ACTIONS TAKEN The repairs efforts included trying to electrically weld the connections by electrical "Zapping".

This method has proven effective at Turkey Point Station but failed to provide the results needed to place the RVLMS system in service and exit Tech. Spec. 3.3.3.6 Table 3.3-10.

Long Term:

Troubleshooting and repair of the RVLMS cables and connections are scheduled to be performed in the next Unit # 2 refueling outage. (SL2-21)

V. SCHEDULE FOR RESTORING SYSTEM The RVLMS "A" Channel HJTC will be restored after Post Maintenance Testing performed at the end of the refueling SL2-21 outage.

St. Lucie Unit 2 L-2013-217 Docket No. 50-389 Attachment Page 2 of 2 Attachment # I Tech. Spec.

Technical Specification 3.3.3.6 The accident monitoring instrumentationchannels shown in Table 3.3-10 shall be OPERABLE.

APPLICABILITY: MODES 1, 2 and 3.

ACTION:

a.

• With the number of OPERABLE accident monitoring channels less than the Required Number of Channels shown in Table 3.3-10, either restore the inoperablechannel to OPERABLE status within 7 days, or be in HOT STANDBY in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and HOT SHUTDOWN in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

b.

• With the number of OPERABLE accident monitoring channels less than the Minimum Channels OPERABLE requirements of Table 3.3-10, either restore the inoperable channels to OPERABLE status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or be in HOT STANDBY in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and HOT SHUTDOWN in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

c. **With the number of OPERABLE Channels one less than the Total Number of Channels shown in Table 3.3-10, either restore the inoperable channel to OPERABLE status within 7 days if repairs are feasible without shutting down orprepare and submit a Special Report to the Commission pursuant to Specification 6.9.2 within 30 days following the event outlining the action taken, the cause of the inoperabilityand the plans and schedule for restoring the system to OPERABLE status.

d.**With the number of OPERABLE Channels less than the Minimum Channels OPERABLE requirements of Table 3.3-10, eitherrestore the inoperable channel(s) to OPERABLE status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> if repairs are feasible without shutting down or:

1. Initiate an alternate method of monitoring the reactorvessel inventory; And

2. Prepareand submit a Special Report to the Commission pursuant to Specification 6.9.2 within 30 days following the event outlining the action taken, the cause of the inoperabilityand the plans and schedule for restoring the system to OPERABLE status, and

3. Restore the Channel to OPERABLE status at the next scheduled refueling.

e. The provisions of Specification 3.0.4 are not applicable.