NL-08-036, Supplemental Submittal Regarding 10 CFR 50.55a Inservice Testing Program Relief Request P-2 for Recirculation Pump Testing

Supplemental Submittal Regarding 10 CFR 50.55a Inservice Testing Program Relief Request P-2 for Recirculation Pump Testing

ML080640827
Person / Time
Site:	Indian Point
Issue date:	02/25/2008
From:	Robert Walpole Entergy Nuclear Indian Point 2
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-08-036
Download: ML080640827 (8)

Text

Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 ffp2 Buchanan, N.Y. 10511-0249 Tel (914) 734-6710 February 25, 2008 Re: Indian Point Nuclear Generating Unit 2 Docket No. 50-247 NL-08-036 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

Supplemental Submittal Regarding 10 CFR 50.55a Inservice Testing Program Relief Request P-2 for Recirculation Pump Testing

References:

1. Entergy letter NL-07-028 to NRC, "Inservice Testing Program Summary for the 4 th Interval, Revision 0," dated February 28, 2007.

2. Entergy letter NL-07-157 to NRC, "10 CFR 50.55a Inservice Testing Program Relief Request P-1 Regarding Recirculation Pump Testing,"

dated December 18, 2007.

Dear Sir or Madam:

Entergy Nuclear Operations, Inc. (Entergy) submitted the 4th Ten-Year Interval Inservice Testing Program Plan for the period March 1, 2007 through April 3, 2016 for Indian Point Unit 2 (IP2). The 4 th Ten-year interval Inservice Testing Program in Reference 1 commenced March 1, 2007 and incorporated the 1995 Edition with the 2003 Addenda of the OM Code as required by 10 CFR 50.55a(b)(3).

A new requirement for the 4th interval involves testing of certain pumps at a flowrate that is within + 20% of the pump design flowrate. The existing configuration of the IP2 recirculation piping associated with the Containment Recirculation Pumps does not allow for testing at this flowrate. Therefore, Reference 2 was submitted by Entergy requesting relief from ASME OM Code requirements, in accordance with 10 CFR 50.55(a)(3), to use a proposed alternative for testing the Containment Recirculation Pumps. Compliance with the new requirement for the 4 th interval requires a modification of IP2 system piping inside containment.

Entergy is hereby submitting a second proposed alternative to the ASME OM Code requirements, in accordance with 10 CFR 50.55(a)(3), in requesting an extension to the performance of the full flow rate test from the current refueling outage, until the following scheduled refueling outage, 2R1 9. This relief would allow us to delay the installation of the piping modification require for the + 20% of the pump design flowrate testing for two years, from the 2008 scheduled refueling outage 2R1 8 (March 25 - April 2008), until the following scheduled IP2 refueling outage, 2R19 in the spring of 2010.

NL-08-036 Docket No. 50-247 Page 2 of 2 Entergy requests the NRC review this relief request (P-2) in parallel and within the same time frame as the previously submitted relief request (P-i) in Reference 2, and requests a response to this request by March 20, 2008.

There are no new commitments contained in this letter.

If you have any questions or require additional information, please contact Mr. Robert Walpole, Manager, Licensing at 914-734-6710.

Sincerely, Robert Walpole Manager, Licensing Indian Point Energy Center cc: Mr. John P. Boska, Senior Project Manager, NRC NRR DORL Mr. Samuel J. Collins, Regional Administrator, NRC Region I NRC Resident Inspector's Office Indian Point Mr. Paul Eddy, New York State Department of Public Service Mr. Paul D. Tonko, President NYSERDA

ATTACHMENT 1 TO NL-08-036 INDIAN POINT 2 SECOND IST RELIEF REQUEST P-2 REGARDING RECIRCULATION PUMP FLOWRATE TESTING ENTERGY NUCLEAR OPERATIONS, INC.

INDIAN POINT GENERATING UNIT NO. 2 DOCKET NO. 50-247

NL-08-036 Docket No. 50-247 Attachment 1 INDIAN POINT UNIT 2 10 CFR 50.55a ISI RELIEF REQUEST P-2 Proposed Alternative In Accordance with 10 CFR 50.55a(a)(3)(i)

Alternative Provides Acceptable Level of Quality and Safety A. ASME Code Component Affected System: Emergency Core Cooling System Component: Containment Recirculation Pumps; 21 RP and 22RP Group: B Class: 2 Function: The Containment Recirculation Pumps are standby pumps which are credited for mitigating the effects of certain hypothetical accident scenarios. These pumps take suction from the recirculation sump in the containment floor and deliver spilled reactor coolant and borated refueling water backto the core through the residual heat exchangers. The pumps do not have any function for support of normal plant operation.

B. Applicable Code Edition and Addenda The applicable-Code edition and addenda are ASME Code for Operation and Maintenance of Nuclear Power Plants (OM), 2001 Edition through 2003 Addenda, which is being invoked for the 4 th Ten-year interval; March 1, 2007 through April 3, 2016.

C. Applicable Code Requirement ISTB-3300(e)(1), "Reference Values", requires that reference values shall be established within +/-20% of pump design flow rate for comprehensive tests.

D. Reason for Request The new requirement of ISTB-3300(e)(1) applicable for the 4 th Ten-year interval cannot be met with the existing configuration of the recirculation piping associated with the Containment Recirculation Pumps. Compliance with the new requirement will require a modification of the system piping.

The design flowrate of the Containment Recirculation Pumps is 3000 gpm so that a test reference value of +/- 20% of the design flowrate per ISTB-3300(e)(1) would require testing at 2400-3600 gpm. The existing recirculation piping for these pumps is a 2-inch diameter which supports a nominal test flowrate of 300 gpm, or 10% of the design flowrate. Testing at 80-120% of the design flowrate will require a plant modification to replace the existing 2-inch diameter recirculation piping with 6-inch diameter piping.

The pumps and the recirculation piping are located in the sump which has limited accessibility and open space as a result of the installation of enhanced suction strainers which provide for improved performance under the new debris blocking assumptions.

The modification to meet the new requirement for the 4th interval involves flowrate that is 1

NL-08-036 Docket No. 50-247 Attachment 1 within + 20% of the pump design flowrate will conflict with the modification to the IP2 sump being completed to meet the requirements of GSI-1 91.

The work in Containment during IP2 2R18 refueling outage for the completion of the sump modification in support of GSI-191 would be performed just below the modification work required for the new full flowrate pump testing. Both of these modifications will require workers to be working in the same area of Containment at the same time with very limited space. This leads to issues and problems with industrial safety and increase dose.

Therefore, Entergy is requesting an extension to the timing of the installation of the modification. Entergy is requesting delaying the modification two years, from the 2008 scheduled refueling outage 2R1 8 (March 25 - April 2008), until the following scheduled IP2 refueling outage, 2R19 in the spring of 2010.

E. Proposed Alternative and Basis for Use The proposed alternative consists of a pump test flowrate of 300 gpm which is 10% of the 3000 gpm design flow. The pump curve for these Ingersoll-Dresser pumps is shown in Figure Two for information. This flowrate is an increase over the 160 gpm test flowrate which was applicable for the previous IST 10-year intervals. Engineering analysis confirms that 300 gpm is achievable with the existing system configuration and does not introduce a risk of localized cavitation at the pump suction. Pump vibration will be measured and recorded in accordance with the criteria specified in the Code.

Vibration spectral analysis will also be performed which is a more accurate method of detecting mechanical degradation or changes than that of the traditional inservice test vibration requirements.

In addition, motor current analysis will be used for each pump motor in the 2R1 8 refueling outage to ensure the motor meets test specifications. The analysis examines the motor for: winding resistance, insulation resistance, polarization index, and motor circuit evaluation. This methodology is used to detect degraded insulation, high resistance shorts and grounds, and the integrity of all motor connections. The predictive maintenance tasks for spectral bearing vibration analysis and motor current analysis will provide additional assurance of operational readiness. With a lack of any significant wear degradation mechanisms, the most likely cause for these pumps to be unavailable would be an electrical fault. The motors are environmentally qualified and the motor current analysis tasks ensure that possible problems are detected and remedied in a timely manner.

The Recirculation Pumps were replaced in 2000 and testing has consistently demonstrated satisfactory performance within the narrow acceptance band established by Engineering for these pumps. A major modification to the pump suction strainer capability for these pumps was completed in 2006. The test arrangement permits testing of the Recirculation Pumps without wetting of the suction strainer mesh filtration system.

The analysis values for minimum and maximum head result in an acceptable operation band which is more conservative than the reduced band allowed in table ISTB-5200-1 used for comprehensive testing. Therefore, degradation will be monitored and action taken conservatively with respect to the Code.

2

NL-08-036 Docket No. 50-247 Attachment 1 In addition, the pump is located in a dry sump section (separated by a weir from the strainer assembly). The pump is only operated at refueling frequency for Code test purposes. The pump does not contain any liquid when not in use. When the test is conducted, the sump section is filled with non-borated water which is removed after the test. Therefore, there is no degradation mechanism which could result in reducing pump effectiveness over time.

The proposed alternative provides a means of assuring the performance capability of these pumps in 2R18, and provides an acceptable level of quality and safety.

F. Duration of Proposed Alternative The proposed alternate testing, consisting of a flow test of at least 10% of design flow, special vibration monitoring and motor current analysis will be preformed on the pumps during the 2008 refueling outage.

3

NL-08-036 Docket No. 50-247 Attachment 1 IP2 Relief Request P-1 Figure One - Test Loop Sketch From IP2 Plant Drawing 235296 t II1 4

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