L-MT-03-001, Relief Request No. Pr 06 for Fourth 10-Year Inservice Testing Interval - High Pressure Coolant Injection Pump Testing

Relief Request No. Pr 06 for Fourth 10-Year Inservice Testing Interval - High Pressure Coolant Injection Pump Testing

ML031350745
Person / Time
Site:	Monticello
Issue date:	05/06/2003
From:	Denise Wilson Nuclear Management Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-MT-03-0018, PR-06
Download: ML031350745 (13)

Text

m Monticello Nuclear Generating Plant Committed to Nuclear Excell Operated by Nuclear Management Company, LLC May 6, 2003 L-MT-03-0018 10 CFR Part 50 Section 50.55a(a)

US Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 MONTICELLO NUCLEAR GENERATING PLANT DOCKET 50-263 LICENSE No. DPR-22 RELIEF REQUEST NO. PR 06 FOR THE FOURTH 10-YEAR INSERVICE TESTING INTERVAL - HIGH PRESSURE COOLANT INJECTION PUMP TESTING Reference 1: NRC letter to IES Utilities, "Safety Evaluation of Relief Requests for Duane Arnold Energy Center Inservice Testing Program (TAC No.

M91683)," dated November 21, 1995.

Pursuant to the provisions of 10 CFR 50.55a, the Nuclear Management Company, LLC (NMC) requests NRC authorization of an alternative testing methodology for the Monticello Nuclear Generating Plant (MNGP) High Pressure Coolant Injection (HPC) pump in accordance with 10 CFR 50.55a(a)(3)(i). The alternative testing employs a methodology that follows the guidelines of Code Case OMN-9, "Use of a Pump Curve for Testing. " As discussed in Attachment 1, the proposed alternative testing provides an acceptable level of quality and safety because the method will provide increased accuracy in trending and data analysis. The alternative testing will be performed during the MNGP fourth ten-year Inservice Testing (IST) interval.

This Relief Request has been modeled after a previously approved Relief Request for the Duane Arnold Energy Center Inservice Testing Program Third Ten-Year Interval, identified as their relief request PR-04. The NRC approved the relief request in Reference 1.

The first scheduled test of the HPC pump in the fourth IST interval is to be performed in early August 2003; therefore, the NMC would like to discuss the schedule for NRC review of this Relief Request with the NRC Project Manager for MNGP.

This letter contains no new commitments and no revisions to existing commitments.

2807 West County Road 75

• Monticello, Minnesota 55362-9637 po4 N<

Telephone: 763-295-5151

• Fax: 763-295-1454

USNRC Nuclear Management Company, LLC Page 2 If you have any questions please contact John Fields (763-295-1663).

David L. Wilson Site Vice President Monticello Nuclear Generating Plant cc: Regional Administrator-lIl, NRC NRR Project Manager, NRC Sr. NRC Resident Inspector, NRC State of Minnesota Boiler Inspector Hartford Insurance - MONTICELLO NUCLEAR GENERATING PLANT PUMP RELIEF REQUEST PR-06

ATTACHMENT I NUCLEAR MANAGEMENT COMPANY, LLC MONTICELLO NUCLEAR GENERATING PLANT DOCKET 50-263 May 1, 2003 MONTICELLO NUCLEAR GENERATING PLANT PUMP RELIEF REQUEST PR-06 10 pages follow 1-1

ATTACHMENT I MONTICELLO NUCLEAR GENERATING PLANT PUMP RELIEF REQUEST PR-06 COMPONENT IDENTIFICATION System: High Pressure Coolant Injection (HPC)

Pumps: P-209 P&ID: NH-36250 (M-124)

Pump Group: B Code Class: 2 Examination Category: N/A Item Numbers: ISTB 5.2.3(a), ISTB 5.2.3(b)

==

Description:==

American Society of Mechanical Engineers (ASME) 1995, 1996 Addenda ASME OM Code, Subsection ISTB CODE REQUIREMENTS ISTB 5.2.2(a), 5.2.3(a); The pump shall be operated ... at a speed adjusted to the reference point (+/- 1%) for variable speed drivers.

In conjunction with ISTB 5.2.2(c); System resistance may be varied as necessary to achieve the reference point.

ISTB 5.2.3(b); The resistance of the system shall be varied until the flow rate equals the reference point. The differential pressure shall then be determined and compared to its reference value.

BASIS FOR RELIEF In order to perform accurate trending and data analysis, the use of an accurate reference value is very important. The complexities of the flow control system used for the Monticello Nuclear Generating Plant (MNGP) HPC pump make it difficult to exactly duplicate the reference points. Additionally, iterative manipulation of the control system equipment to refine the hydraulic and speed parameters contributes additional wear to system components.

As alternative testing is allowed under the provisions of 10CFR50.55a(a)(3)(i), the Nuclear Management Company, LLC (NMC) proposes an alternative test method for the Comprehensive and Group B HPC pump test, as required byASME 1995,1996 Addenda ASME OM Code, Subsection ISTB. The NMC has determined that the proposed alternative test will provide an acceptable level of quality and safety.

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ATTACHMENT 1 PROPOSED ALTERNATIVE PROVISIONS Alternative testing is requested to be authorized in accordance with 10 CFR 50.55a(a)(3)(i). The proposed alternative testing described below provides an acceptable level of quality and safety based upon an increased accuracy in trending and data analysis. The methodology utilized follows the guidelines in Code Case OMN-9, "Use of a Pump Curve for Testing."

Pump Testing Performed The NMC performed a pump performance test on the MNGP HPC pump on February 12, 2003 to gather flow, pressure, speed and vibration data over a range of flow rates while the pump condition was known to be operating acceptably. During this test, pump driver speed was held nominally constant near the reference speed for the duration of the test. Prior to taking data at the test points, HPC pump operation was stabilized (nominally two minutes). Data sets were obtained and the methodology prescribed in Code Case OMN-9 was utilized (see Tables 1 and 2 and Figures 1 and 2).

Pump flow and differential pressure test data was found to follow the expected 3rd order polynomial curve, which is characteristic of centrifugal pump operation.

During testing, vibration data was taken over an enveloping flow range. Figure 3 through Figure 6 are provided to show that there is no significant variation in vibration readings over the anticipated allowable flow range. The anticipated allowable flow range is planned to be used during Quarterly (Group B) and Comprehensive (Biennial) testing for the HPC pump.

In summary, the overall results of the test indicate the pump operates acceptably with no unexpected anomalies over the range of testing performed. The findings are similar to those concluded by the Duane Arnold Energy Center (DAEC) in their HPC Relief Request PR-04, which is currently approved for their Inservice Testing (ST) 3rd ten-year code interval.

Technical Description of Method The method of obtaining a reference value curve was established using Code Case OMN-9 as a guideline and is similar to DAEC Relief Request PR-04. In the MNGP HPC pump testing the NMC produced flow, vibration, pressure and speed data points over an operating range that exceeded that which was necessary to establish the IST allowable pump flow band. As described in this relief request, five data sets (each data set consisted of two readings for flow, pressure, speed and vibration) were analyzed in the development of the pump reference curve. The data sets are distributed across the entire range of potential in-service test conditions.

The reference value curve is computed using a third order polynomial regression technique that employs a least squares fit of the data points. The resulting reference value curve is a third order polynomial in the general form of:

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ATTACHMENT 1 y = a 3x3 +a 2 x2 + ax + aO where: y = dependent variable (psid) x = independent variable (gpm) a1 = constants The Required Action and Alert Range limits are scalar multiples of the reference value curve. Tabular summaries are used as Acceptance Criteria to evaluate the test results (Table 1 and Table 2).

The measurements taken during the test were then analyzed to define the boundaries of the reference value curve. For future surveillance testing, the test differential pressure vs. flow will be plotted on the reference value curve included in the permanent test records. An example of the curve to be used in the permanent test records is shown in Figure 1 and Figure 2. For determination of whether the IST Acceptance Criteria is met, Table 1 and Table 2 will be utilized to analyze the data.

Alternative Testing During Comprehensive and Quarterly HPC Pump Testing, pump differential pressure and flow rate will be evaluated using a reference point derived from a pump curve.

Figure 1 and Figure 2 provide the representative graph that NMC proposes to use for Quarterly and Comprehensive Testing, respectively. The reference point test pump curve will be restricted to an operating range that is representative of accident conditions. Appropriate upper and lower acceptance criteria limits for differential pressure will be established for the Required Action and Alert range limits, as applicable, for Group B (Quarterly) and Comprehensive testing. These limits will be scalar multiples of the reference pump curve. For determination of whether the IST Acceptance Criteria is met, Table 1 and Table 2 will be used to analyze the data.

NMC will follow the stipulations established by MNGP Pump Relief Request PR-03 for the Vibration Alert Levels and Code established limits for the Action Required Levels over the reference value curve range for Comprehensive testing.

The vibration data (see Figure 3 through Figure 6) from the test was reviewed and no adverse correlation was evident between flow rate and vibration at the nominal reference point speed. Therefore, NMC will not establish new vibration reference values and related allowable limits over the reference value curve at this time.

If future conditions warrant generation of a new pump reference curve, the NMC will follow the guidance of Code Case OMN-9 for this activity. If new pump reference curves are generated, the NMC does not intend to provide the curves to the NRC.

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ATTACHMENT 1 CONCLUSION:

Alternative testing authorization is requested in accordance with 10 CFR 50.55a(a)(3)(i).

The alternative testing would allow NMC to follow the guidelines in Code Case OMN-9, "Use of a Pump Curve for Testing". As described above, the alternative testing provides an acceptable level of quality and safety because the method will provide increased accuracy in trending and data analysis. This Relief Request (PR 06) is similar to a Relief Request that was approved by the NRC for the DAEC for their IST 3rd ten-year code interval.

PERIOD FOR WHICH RELIEF IS REQUESTED This alternative is proposed for NMC Monticello Nuclear Plant use during its 4 th Ten-Year Code Interval, beginning June 1, 2003.

Attachments:

Table 1 - "HPC Pump Group B Quarterly Test Acceptance Criteria" Table 2 - "HPC Pump Comprehensive Test Acceptance Criteria" Figure 1 - "HPC P-209 Group B Quarterly Testing Limits" Figure 2 - "HPC P-209 Comprehensive Testing Limits" Figure 3 through Figure 6 - "HPC Vibration Comparison over Reference Curve Flow Range" 1-5

HPC Pump Group B Quarterly Test Acceptance Criteria (For Information Only, actual data may change during 4 th IST Interval)

Table 1 Pump Flow Pump Diff Press Group B uarterly Test Reference Point Reference Value Upper Required Lower Required (gpm) (psid) Action Range Action Range

_______ _______(> psid) (< psid) 2900 1061.4 1167.5 955.3 2950 1057.0 1162.7 951.3 3000 1051.9 1157.0 946.8 3050 1046.0 1150.6 941.4 3100 1039.7 1143.6 935.8 3150 1032.9 1136.1 929.7 3200 1025.9 1128.4 923.4 3250 1018.8 1120.6 917.0 330 1011.6 1112.7 910.5 Figure 1 HPCI P.209 Group BQuartedly Testi Limits Only,Acul ReferenCur a UmbtmaybereVIed)

(ForhiformaJoe 1200

.............................. -I

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1150 i -- - - -

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1 1050 ..

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0 950 900 900 2950 3000 3050 3100 3150 3200 3250 3300 Flow Rate (gpm)

Pumnp RefereniceCurve ... Upper Action LUm - Lower Action Lima]

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HPC Pump Comprehensive Test Acceptance Criteria (For Information Only, actual data may change during 4 th IST Interval)

Table 2 Pump Flow Cor rehensive Test Refeence Reference Pump Reference Diff Press.

Value Upper Required Lower Alert Lower Required (gpm) (psid) Action Range Range Action Range

(> psid) (<psid) (< psid) 2900 1061.4 1093.2 987.2 955.3 2950 1057.0 1088.7 983.1 951.3 3000 1051.9 1083.4 978.3 946.8 3050 1046.0 1077.3 972.8 941.4 3100 1039.7 1070.8 967.0 935.8 3150 1032.9 1063.8 960.6 929.7 3200 1025.9 1056.6 954.1 923.4 3250 1018.8 1049.3 947.5 917.0 3300 1011.6 1041.9 940.8 910.5 Figure 2 HPCI P209 Comprehensive Testina Limits (ForInformaton Only, Ad Rc Cwve ad Llmfts maybe revid) i4rn -

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• Lower Alert Limit . Lower ActiLimll

Figure 3 HPCI Vibration Comparision over Reference Curve Flow Range (2.12.03 Test) 0.5 0.45 A

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Figure 4 HPCI Vibration Comparision over Reference Curve Flow Range (2.12.03 Test) 0.5-0.4 5 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

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Figure 6 HPCI Vibration Comparision over Reference Curve Flow Range n c (2.12.03 Test)

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