GO2-16-161, Response to Request for Additional Information, Columbia Mur LAR: Esgb, Coating and FAC

Response to Request for Additional Information, Columbia Mur LAR: Esgb, Coating and FAC

ML16343B067
Person / Time
Site:	Columbia
Issue date:	12/08/2016
From:	Javorik A Energy Northwest
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CAC MF8060, GO2-16-161
Download: ML16343B067 (9)

Text

Alex L. Javorik ENERGY Columbia Generating Station P.O. Box 968, PE04 NORTHWEST Richland, WA 99352-0968 Ph. 509-377-8555 IF. 509-377-2354 aljavorik@energy-northwest.com December 8, 2016 G02-16-161 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

COLUMBIA GENERATING STATION, DOCKET NO. 50-397 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION, COLUMBIA MUR LAR: ESGB, COATING AND FAC

References:

1. Letter G02-16-096 from A. L. Javorik (Energy Northwest) to NRC:

"License Amendment Request to Revise Operating License and Technical Specifications for Measurement Uncertainty Recapture (MUR) Power Uprate, 11 dated June 28, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16183A365)

2. Letter G02-16-124 from A. L. Javorik (Energy Northwest) to NRC:

"Response to License Amendment Request - Opportunity to Supplement," dated August 18, 2016 (ADAMS ML16231A511)

3. E-mail from J. Klos (NRC) to R. M. Garcia (Energy Northwest) "Request for Additional Information, Columbia MUR LAR: ESGB, Coating and FAC, 11 dated November 1, 2016 (CAC No. MF8060)

Dear Sir or Madam:

By Reference 1, Energy Northwest submitted a license amendment for Columbia Generating Station (Columbia) to recapture certain measurement uncertainty as a power uprate. By Reference 2, Energy Northwest supplemented the original request.

In Reference 3, the NRC requested additional information related to the Columbia submittal. The enclosure to this letter contains the information requested in Reference 3.

The No Significant Hazards Consideration Determination provided in Reference 1 is not altered by this submittal.

No new commitments are being made by this letter or the enclosure. If you have any questions or require additional information, please contact Mr. R. M. Garcia at (509) 377-8463.

G02-16-161 Page 2 of 2 I declare under penalty of perjury that the foregoing is true and correct.

Executed this ~f~ day of 1ecte111//', 2016.

Respectfully, A. L. Ja rik Vice President, Engineering

Enclosure:

As stated cc: NRC RIV Regional Administrator CD Sonoda - BPA/1399 (email)

NRC NRA Project Manager WA Horin -Winston & Strawn NRC Senior Resident lnspector/988C

G02-16-161 Enclosure Page 1 of 4 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FROM THE STEAM GENERATOR TUBE INTEGRITY AND CHEMICAL ENGINEERING BRANCH (ESGB)

Protective Coatings in Containment:

Protective coating systems (paints) provide a means for protecting the surfaces of facilities and equipment from corrosion and contamination from radionuclides and also provide wear protection during plant operation and maintenance activities, and for their suitability for and stability under design basis LOCA accident conditions, considering radiation and chemical effects. The NRC's acceptance criteria for protective coating systems is based on (1) 10 CFR Part 50, Appendix 8, which states quality assurance requirements for the design, fabrication, and construction of safety-related structures, systems, and components (SSCs) and (2) Regulatory Guide (RG) 1.54, Revision 2, Service Level I, II, and Ill Protective Coatings Applied to Nuclear Power Plants. Specific review criteria are contained in SRP Section 6.1.2, Protective Coating Systems (Paints)

- Organic Materials Review Responsibilities.

Consistent with the regulatory requirements stated above, the license amendment request (LAR) dated June 28, 2016 (Agencywide Documents Access Management System (ADAMS) Accession No. ML16183A365, Enclosure 9, Section 4.1.5 Containment Coating states that the service level 1 coatings in containment are qualified to 340 degrees F [Fahrenheit], 70 psi [pounds per square inch], and 1.1 x 106 rads [absorbed radiation dose].

ESGB RAI -1:

In order for the staff to determine whether the coatings will continue to perform their safety function and will not be adversely impacted by the power uprate conditions, provide the containment temperature, pressure, and radiological dose conditions for the expected post-measurement uncertainty recapture power uprate design basis loss of cooling accident [LOCA] environmental conditions.

ENERGY NORTHWEST RESPONSE TO ESGB RAI - 1:

The current Columbia containment analyses for design basis accident (DBA)-LOCA Long-term and Short-term Containment Responses in References 1, 2, 3 and 4 have been reviewed. The limiting containment pressure, temperature, and radiological dose for DBA-LOCA are provided in the following tables. These values are acceptable for limiting environmental conditions in the containment for DBA-LOCA post-accident conditions.

Parameters Limiting Value (1l Design Limit (1l 52.1 < 59.7 Peak Drywell Pressure (psia)

(37.4 psig) (45 psig)

Peak Containment Temperature (°F) 328.0 <340 (i ) These values are based on References 1, 2, 3 and 4.

G02-16-161 Enclosure Page 2 of 4 Location Service Dose Accident Gamma Dose Total Integrated Dose(2 )

Dry Well 5.025E+07 5.361E+07 1.039E+08 Wetwell 1.755E+07 9.468E+07 1.122E+08 2

< l The total integrated dose is the sum of the service dose and accident gamma dose.

During the review of the requested information, Energy Northwest identified that the Service Level 1 qualification for integrated dose stated in Enclosure 7 of Reference 1 contained a typographical error. The statement is corrected to:

The Service Level 1 coatings are qualified to 340°F, 70 psig, and 1x109 rads. Therefore, the containment coatings continue to bound the OBA temperature, pressure, and radiation at TPO conditions.

Flow Accelerated Corrosion (FAC):

FAC is a corrosion mechanism occurring in carbon steel components exposed to single-phase or two-phase water flow. Components made from stainless steel are immune to FAC, and FAC is significantly reduced in components containing even small amounts of chromium or molybdenum. The rates of material loss due to FAC depend on the system flow velocity, component geometry, fluid temperature, steam quality, oxygen content, and pH. During plant operation, it is not normally possible to maintain all of these parameters in a regime that minimizes FAC; therefore, loss of material by FAC can occur and the rate of material loss needs to be predicted so that repair or replacement of damaged components could be made before reaching a critical thickness. The NRC's acceptance criteria are based on the structural evaluation of the minimum acceptable wall thickness for the components undergoing degradation by FAC.

ESGB RAI - 2:

The measurement uncertainty recapture (MUR) power uprate will affect several process variables that influence FAC. Identify the systems (e.g. main steam, feedwater, and balance of plant systems) that are expected to experience the greatest increase in wear as a result of the power uprate and discuss the effect of individual process variables (i.e., moisture content, temperature, oxygen, and flow velocity) on each system identified. For the most susceptible components, provide the predicted increase in wear rate due to FAC as a result of power uprate conditions.

ENERGY NORTHWEST RESPONSE TO ESGB RAI - 2:

The table in the attachment to this letter lists the systems analyzed and the changes in moisture content (steam quality), temperature, and flow velocity that were due to MUR power uprate.

The dissolved oxygen content as well as pH is calculated by the Water Chemistry module of CHECWORKS' Steam/Feedwater Application (SFA). This information is

G02-16-161 Enclosure Page 3 of 4 linked to the plant model by associating a cycle specific water treatment with each plant operating period.

The CHECWORKS' SFA model was updated for plant operation during cycle P22 and refueling outage R22. Specifically, water treatment information was updated with actual chemistry parameters for operating cycle P22. In addition, a change to the estimate of steam line dissolved oxygen for all operating cycles since the implementation of hydrogen water chemistry was made. Therefore, the model was updated with a revised steam line dissolved oxygen value of 1ppm.

Lines containing water with high levels of dissolved oxygen (typically greater than 1000 ppb) are not considered susceptible to FAC and can be excluded from further analysis.

The dissolved oxygen concentration for fresh water exposed to the atmosphere varies with temperature. Expected range is 14,560 ppb (32F) to 7560 ppb (86F). Systems normally meeting this criterion include service water, circulating water, and fire protection.

After refueling outage R22 (spring 2015), the current plant conditions, actual outage measurements, chemistry changes and proposed MUR power uprate data were updated into the current Steam/Feedwater Application (SFA) model. The proposed MUR power uprate thermodynamic conditions were updated in CHECWORKS'. The expected results are identified in the SFA model update report and flow chart.

As can be seen in the attachment to this enclosure, there are no overall systems or individual components that will reach an increase wear rate of 20% or higher. The highest average rate of wear change is 16% while the highest individual location(s) are not over 17%.

ESGB RAI - 3:

In April 2013, a through wall leak was discovered in the reactor water cleanup (RWCU) system at Columbia Generating Station. This leak appeared to be the result of FAC (as stated by the licensee in a relief request dated April 5, 2013, ADAMS Accession No. ML13108A218).

Accordingly, the staff requests that the licensee provide a summary of the corrective actions taken that impacted the FAC monitoring program, as a result of this operating experience, to include;

• a sample list of components for which wall thinning is predicted and measured by ultrasonic testing or other methods that includes the initial wall thickness (nominal),

current (measured) wall thickness, and a comparison of the measured wall thickness to the thickness predicted by the model,

• confirmation that the CHECWORKS' predictive modeling software is still used; and

• changes to the input for the predictive method to calculate wall thinning due to FAC that have been made.

G02-16-161 Enclosure Page 4 of 4 In addition, please describe any impacts that the proposed MUR power uprate may have on areas that were impacted by this operating experience above, such as, if the inspection frequency or scope has changed.

ENERGY NORTHWEST RESPONSE TO ESGB RAI - 3:

The attachment to this enclosure provides the CHECWORKS' SFA Model Update showing the predicted wall thinning.

The CHECWORKS' predictive modeling software continues to be used at Columbia.

As a result of the RWCU operating experience the CHECWORKS' predictive method was updated to include improved water chemistry estimates for the entire plant.

The changes to the FAC program are complete and no updates were required for the RWCU system inspection frequency or scope as a result of the MUR updates.

References

1. GE Nuclear Energy, "WNP-2 Power Uprate Project NSSS Engineering Report" GE-NE- 208-17-0993 Revision 1, December 1994.

2. GE Nuclear Energy, "Power Uprate with Extended Load Line Limit Safety Analysis for WNP-2," NEDC-32141 P Revision 0, June 1993.

3. GE Hitachi Nuclear Energy, "ENERGY NORTHWEST Columbia Generating Station APRM/RBM!fechnical Specifications I Maximum Extended Load Line Limit Analysis (ARTS/MELLLA)" NEDC-33507P Revision 1, January 2012.

4. GE Hitachi Nuclear Energy, "Technical Specification Change Support for RHR/LPCI and LPCS Flow Rate Long-Term LOCA Containment Response and ECCS/Non-LOCA Evaluations," NEDC-33813P Revision 2, September 2013.

G02-16-161 Attachment ALTRN Report 12-1410-TR-003 Revision 1 Flow Accelerated Corrosion Program - CHECWORKS' SFA Model Update Attachment K FAC Changes Due To MUR

I RPT. NO. 12*141 O*TR*003 Rev a LTRa n I 1 PAGE K*2 OF K*3 CLIENT/PROJECT I Energy Northwest I Col umbia Generating Station TITLE I Flow Accelerated Corrosion Prog ram - CHECWORKS"' SFA Model Update 1 Condensate: Condensate to FWH3 65 4% 5% 4% 9.3 200.3 1.7 0.0000 0.0000 12.3 4% Run experienced an increase in predicted FAC Wear Rate 2 Condensate: Condensate to FWH4 28 4% 4% 4% 13.6 252.6 2.0 0.0000 0.0000 13.2 4% Run experienced an increase in predicted FAC Wear Rate 3 Condensate: Condensate to FWH5 70 3% 4% 3% 15.0 287.4 2.1 0.0000 0.0000 12.4 4.20..<i Run experienced an increase in predicted FAC Wear Rate 4 Condensate: Condensate to RFWP 180 -2% 0% -3% 7.6 367.2 3.0 0.0000 0.0000 8.3 2.4% Run experienced a decrease in predicted FAC Wear Rate 5 Reactor Feedwater: Feedwater to FWH6 96 -1% 0% -1% 18.6 367.2 3.0 0.0000 0.0000 19.1 4.3% Run experienced a decrease in predicted FAC Wear Rate Reactor Feedwater: Feedwater to Run experienced an increase in predicted FAC Wear Rate 6 213 3% 3% 0% 12.9 422.8 3.4 0.0000 0.0000 18.8 4.20..<i Reactor 7 Heater Drains: FWH6 to FWH5 60 -5% -4% -6% 8.6 378.8 2.9 0.0004 0.0000 8.2 4.4% Run experienced a decrease in predicted FAC Wear Rate 8 Heater Drains: FWH5 to FWH4 149 2% 3% -1% 17.5 297.3 2.1 0.0004 0.0000 10.4 4.9% Run experienced an increase in predicted FAC Wear Rate 9 Heater Drains: FWH4 to FWH3 48 -2% -1% -6% 14.7 262.4 2.0 0.0004 0.0000 9.7 4.9% Run experienced a decrease in predicted FAC Wear Rate 10 Heater Drains: FWH3 to FWH2 61 3% 3% 1% 30.3 210.2 1.7 0. 0003 0.0000 8.8 5% Run experienced an increase in predicted FAC Wear Rate 11 Heater Drains: FWH2 to FWH1 76 4% 6% 4% 15.0 174.4 1.4 0.0000 0.0000 7.6 5% Run experienced an increase in predicted FAC Wear Rate 12 Heater Drains: FWH1 to Condenser 66 4% 6% 3% 5.2 125.4 -1 .6 0.0001 0.0000 7.9 6% Run experienced an increase in predicted FAC Wear Rate Two Tees were exduded from the results of this analysis due 13 I Bleed Steam: HP Turbine to FWH6 50 6% 7% -6% 6.8 435.3 6.1 0.8859 -0.0026 36.3 10% to a high percent change of Wear Rate but less than 1 mil/year of WearRate Heater Drains: Re-Heater 2 Tank Drains Run experienced a decrease in predicted FAC Wear Rate 14 1 202 -7% -7% -7% 18.9 538.5 1.1 0.0137 -0.0024 5.2 -2%

to FWH6 Includes Gland Seal Steam. Run experienced an increase in 15 I Bleed Steam: HP Turbine to MSR 229 4% 12% 0% 4.2 449.3 2.4 0.9110 -0.0023 15.2 4%

predicted FAC Wear Rate Heater Drains: Moisture Separator to Includes Pre-Separator drains. Run experienced an increase 16 1 660 1% 3% -8% 3.7 376.1 1.4 0.0105 -0.0005 2.5 20..<i FWH5 in predicted FAC Wear Rate Heater Drains: Re-Heater 1 Tank Drains Run experienced an increase in predicted FAC Wear Rate 17 186 6% 7% 5% 6.5 447.9 4.6 0.0073 -0.0014 3.3 3%

to FWH6 18 Bleed Steam: LP Turbine to FWH3 180 16% 17% 8% 8.3 259.1 2.0 0.9870 -0.0015 2.6 20% Run experienced an increase in predicted FAC Wear Rate 19 Bleed Steam: LP Turbine to FWH2 179 3% 11% 2% 9.3 206.6 3.1 0.7547 -0.0045 5.3 15% Run experienced an increase in predicted FAC Wear Rate 20 Reactor Water Clean Up: Entire System 339 0% 0% 0% 12.4 483.7 0.0 0.0000 0.0000 5.6 0% RWCU conditions did not vary with Power Level.

Total Components Analyzed= 3137 (1) Values in GREEN show where FAC has decreased while values in RED show where FAC has increased. In the wear rate change columns negative values are GREEN and positive values are RED.

(2) Average Post wear rate is based on Pass 2 predictions (calibrated to inspection data).

(3) In the temperature change field, values that move toward the FAC peak (at-275 deg F for 1-phase and 300 deg F for 2-phase) are RED while those that move away from the peak are GREEN. Values that are near the FAC peak where the impact is unknown are black.

(4) In the quality change field, values that move toward the FAC peak (at-50%) are RED while those that move away from the peak are GREEN. Values that are near the FAC peak where the impact is unknown are black.

(5) Values in GREEN show where velocity/flow rate has decreased while values in RED show where flow rate has increased. FAC rates increase with increasing flow rates and decrease with decreasing flow rates.

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