3F0698-17, Submits Results of Evaluation to NRC Re GL 87-02, Verification of Seismic Adequacy of Mechanical of Condenser & Electrical Equipment in Operating Reactors (USI A-46) for Evaluation of Condenser Hotwell Suction Isolation Valve

Submits Results of Evaluation to NRC Re GL 87-02, Verification of Seismic Adequacy of Mechanical of Condenser & Electrical Equipment in Operating Reactors (USI A-46) for Evaluation of Condenser Hotwell Suction Isolation Valve

ML20248H803
Person / Time
Site:	Crystal River
Issue date:	06/01/1998
From:	Baumstark J FLORIDA POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR 3F0698-17, 3F698-17, GL-87-02, GL-87-2, TAC-M69440, NUDOCS 9806080254
Download: ML20248H803 (8)

Text

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e Flzrida Power  !

CORPORATION N .76 Iso Opsesting License No. DPA 72 l

June 1,1998 3F0698-17 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

Subject:

Generic Letter 87-02, " Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors (USI A-46)" - Evaluation of Condenser llotwell Suction Isolation Valve (TAC No. M69440)

References:

1. NRC to FPC letter dated February 2,1998 (3N0298-01)

2. FPC to NRC letter dated March 30,1998 (3F0398-16)

Dear Sir:

By letter dated February 2,1998, the NRC forwarded a request for additional information (RAI) regarding the verification of seismic adequacy of mechanical and electrical equipment in operating reactors, Unresolved Safety Issue (USI) A-46, to Florida Power Corporation (FPC).

A response to the RAI was provided by letter dated March 30,1998 (Reference 2).

In Reference 2, Attachment C, Availability of Condensate Sources, a closed manual valve in the piping between the condenser hotwell and the suction of both emergency feedwater pumps (EFPs) was discussed. As stated in Reference 2, this manual valve (EFV-36) must be opened to transfer EFP suction to the hotwell, and if this valve failed to open access to about 150,000 gallons of condensate grade water for Emergency Feedwater (EFW) would be eliminated. FPC committed to evaluate the advantages of returning EFV-36 to a normally open status to eliminate this potential single failure, and to submit the results of the evaluation to the NRC by June 1, 1998.

The evaluation, discussed in Attachment B, concluded that EFV-36 should remain closed for fuel Cycle 11. The decision to leave EFV-36 closed following the Cycle 11 refueling outage will be based on the outcome of maintenance activities to correct the leakage on EFV-1 and EFV-2, as discussed in Attachment B, to be completed during the outage. FPC will notify the NRC of the final resolution prior to restart from refueling outage 11, currently scheduled for Fall 1999.  !

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~' I 9906000254 990601 PDR ADOCK 05000302

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P PDR CRYSTAL RIVER ENERGY oCMPLEX: 15760 W. Power une Street

• Crystal fUver. FL 34428-6708 * (352) 795-6486 A Tkdde Progress Company u )

. .U.S.' Nuclear Regulatory Commission 3F0698-17 Page 2 of 2 Il you l$ ave any questions regarding this submittal, please contact Ms. Sherry Bernhoft, Manager, Nuclear Licensing at (352) 563-4566.

Sincerely, 6 \

s J. 'S. aumstark Director, Nuclear Engineering and Projects

! SLB/rer Attachments:

A. List of Regulatory Commitments B. Evaluation of Returning EFV-36, Condenser Hotwell isolation Valve, to Normally Open Position xc: Regional Administrator, Region 11 Senior Resident Inspector NRR Project Manager

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l FLORIDA POWER CORPORATION CRYSTAL RIVER UNIT 3 DOCKET NUMBER 50-302/ LICENSE NUMBER DPR-72 ATTACIIMENT A LIST OF REGULATORY COMMITMENTS l

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. U.S. Nuclear Regulatory Commission Attachment A

( 3F0698-17 Page1 of1 )

ATTACKh1ENT A LIST OF REGULATORY COMMITMENTS The following table identifies those actions committed to by Florida Power Corporation in this I document. Any other actions discussed in the submittal represent intended to planned actions l by Florida Power Corporation. They are described to the NRC for the NRC's information and l are not regulatory commitments. Please notify the Manager, Nuclear Licensing of any questions l regarding this document or any associated regulatory commitments.

Commitment Due Date FPC will determine and implement the final resolution of Prior to restart from the EFV-1 and EFV-2 leakage and EFV-36 position and will Cycle 11 refueling outage notify the NRC of completion.

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l FLORIDA POWER CORPORATION CRYSTAL RIVER UNIT 3 DOCKET NUMBER 50-392/ LICENSE NUMBER DPR-72 ATTACHMENTS j l

EVALUATION OF RETURNING EFV-36, CONDENSER HOTWELL ISOLATION ~>'ALVE, TO NORMALLY OPEN POSITION

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- U.S. Nuclear Regulatory Commission Attachment B

} 3F0698-17 Page 1 of 3 l

ATTACIIMENT B EVALUATION OF RETURNING EFV-36, CONDENSER llOTWELL ISOLATION VALVE, TO NORMALLY OPEN POSITION i

Currentflant Continuation

j. A simplified flow diagram showing the piping and valves between the condenser and the

emergency feedwater pumps is provided as Figure 1.

l The valve in the suction line to the emergency feedwater pumps (EFPs) from the main condenser hotwell is EFV-36. This valve is currently maintained closed. Consequently, EFV-36 must be opened to provide inventory from the hotwell to the suctior, of the Emergency Feedwater Pumps (EFP-1 and EFP-2). This condition is inconsistent with con.mitments made in the Crystal River Unit 3 (CR-3) response to Generic Letter 87-02, dated August 15,1994 (3F0894-02).

Commitments made in that letter and in the Plant Specific Procedure (PSP) for resolution of USI A-46 require CR-3 to be capable of achieving and maintaining safe shutdown conditions for at least 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. No single failure can preclude this capability. The failure of EFV-36 to manually open would make 150,000 gallons of water from the condenser hotwell unavailable and limit the time CR-3 could maintain hot standby to approximately 42 hours4.861111e-4 days <br />0.0117 hours <br />6.944444e-5 weeks <br />1.5981e-5 months <br />.

EFV-36 was placed in the normally closed position in 1994 due to leakage past EFV-1 and EFV-2, the suction isolation valves from the main condenser hotwell to EFP-2 and EFP-1, respectively. This leakage results in a loss of Emergency Feedwater Tank (EFT-2) inventory to the hotwell. Prior to closing EFV-36, significant operator attention was required to ensure that the EFT-2 level remained greater than the minimum volume required by the CR-3 Improved Technical Specifications. Additional operator burden was created by the need for chemical additions and tank recirculation once inventory was restored to EFT-2. Closure of EFV-36 stopped the loss of EFT-2 inventory to the hotwell and eliminated the operator burden.

EFV-1 and EFV-2 were rebuilt during the recent 1997 shutdown in an attelopt to eliminate the leakage problem. The valves were shop tested for leak-tightness by means of applying a blue dye to the valve disc and evaluating the seating of the disc to the valve seat (referred to as " blue checking"). The results of this test were judged to be satisfactory. Based on the satisfactory results of the shop test a post-maintenance test was not performed.

. U.S. Nuclear Regulatory Commission Attachment B 3F0698-17 Page 2 of 3 Evaluation Performed and Results EFV-36 was opened on April 28, 1998 in order to quantify the amount of leakage past the normally closed valves EFV-1 and EFV-2. The leakage past these valves was estimated to be approximately 10 gpm. This leakage rate is unacceptably high since operators would be required to refill EFT-2 approximately once per day to maintain the level between the high and low level alarm limits. EFV-36 was re-closed after the leakage data was obtained.

The high leakage rate past EFV-1 and EFV-2 has been formally documented in accordance with CR-3's Corrective Action Program. Based on the high leakage rate of EFV-1 and EFV-2, and the inability to correct the leakage while at power, EFV-36 will remain closed for the remainder of fuel Cycle 11. Operation with EFV-36 closed is considered to have low safety significance.

This is based on the inherent seismic ruggedness of manual operated valves and the unlikely failure of this valve to operate (i.e., manual valves have a low incidence of failure).

' Additionally, in the unlikely event that EFV-36 did fail to open, CR-3 has the ability to establish a flow path which would provide EFW with inventory from numerous other sources. These sources are identified in FSAR Table 10-2A, " Preferred EFW Sources," and in FSAR Table 10-2B, "Other EFW Sources." In addition, EM-225, " Duties of the Technical Support Center Accident Assessment Team," contains guidance to begin preparations for a backup emergency feedwater source in case the existing source degrades or fails. The above considerations, when combined with the low seismicity of the CR-3 area, supports the conclusion of low safety significance.

Follow-up Actions The repair activities on EFV-1 and EFV-2 must be performed during a refueling outage since intrusive maintenance activities on these valves to correct the leakage are not possible with CR-3 at power. Further actions to eliminate leakage past these valves will be scheduled for the next refueling outage (Cycle 11). The success of these activities will determine the course of action l

for final resolution of this issue.

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U.S. Nuclear Regulatory Commission Attachment B 3F0698-17 Page 3 of 3 FIGURE 1 SIMPLIFIED FLOW DIAGRAM OF PORTION OF EMERGENCY FEEDWATER SYSTEM LA (

FT EFV-2 EFP-1 EFV-3 To OTSGs -

EFT-2 f-L EFV-4

]I CONDENSER LJ LJ (

HOTWELL Fl F1 EFV-36 EFV-1 EFP-2 l

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