ML052630441
| ML052630441 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 09/16/2005 |
| From: | Harris A Entergy Nuclear South, Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-04-002, W3F1-2005-0063 | |
| Download: ML052630441 (18) | |
Text
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Entergy Nuclear South Entergy Operations, Inc.
17265 River Road
-m Killona, LA 70057-3093 nte gyTel 504-739-6475 En t egy Fax 504-739-6698 aharris@entergy.com Alan J. Harris Director, Nuclear Safety Assurance Waterford 3 W3FI-2005-0063 September 16, 2005 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001
Subject:
Response to Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors" Waterford Steam Electric Station, Unit 3 (Waterford 3)
Docket No. 50-382 License No. NPF-38
Dear Sir or Madam:
By Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors, dated September 13, 2004, the NRC requested licensees to provide a response by September 1, 2005. On August 30, 2005, Entergy informed the NRC project manager that this submittal would be delayed due to the mandatory evacuation of the New Orleans area because of Hurricane Katrina. The requested information for Waterford 3 (W-3) is provided in to this submittal.
New commitments contained in this submittal are summarized in Attachment 2. Should you have any questions concerning this submittal, please contact Mr. Greg Scott at 504-739-6703.
I declare under penalty of perjury that the foregoing is true and correct. Executed on September 16, 2005.
Sincerely, AJH/GCS/cbh Attachments
W3Fl-2005-0063 Page 2 cc:
Dr. Bruce S. Mallett Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Waterford Steam Electric Station Unit 3 P.O. Box 822 Killona, LA 70066-0751 U. S. Nuclear Regulatory Commission Attn: Mr. N. Kalyanam Mail Stop O-07D1 Washington, DC 20555-0001 Wise, Carter, Child & Caraway ATTN: J. Smith P.O. Box 651 Jackson, MS 39205 Winston & Strawn ATTN: N.S. Reynolds 1700 K Street, NW Washington, DC 20006-3817 Morgan, Lewis & Bockius LLP ATTN: T.C. Poindexter 1111 Pennsylvania Avenue, NW Washington, DC 20004
Attachment I W3FI-2005-0063 to W3F1 -2005-0063 Page 1 of 12 W-3 Response
- 2. Addressees are requested to provide the following information no later than September 1, 2005:
(a) Confirmation that the emergency core cooling system (ECCS) and containment spray system (CSS) recirculation functions under debris loading conditions are or will be in compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of this generic letter. This submittal should address the configuration of the plant that will exist once all modifications required for regulatory compliance have been made and this licensing basis has been updated to reflect the results of the analysis described above.
The W-3 ECCS and CSS recirculation functions will be in compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of the subject generic letter under debris loading conditions. Response 2(b), below, describes the actions required to ensure this compliance. Additional information provided relates to the plant configurations following completion of the described actions.
The containment walkdowns, debris generation calculation, debris transport and head-loss calculation, downstream effects evaluations for blockage, and the procurement specifications are essentially completed. The downstream effects evaluation for long-term wear is in progress and is scheduled to be completed by December 20 2005. The results will be submitted to the NRC by December 15, 2005. The W-3 sump strainer vendor selection is also planned to be completed by December 20, 2005. Sargent and Lundy has performed the generic safety issue (GSI)-191 evaluations. The evaluation of the fuel for downstream effects is being performed by Westinghouse. This response is based on the currently available information.
(b) A general description of and implementation schedule for all corrective actions, including any plant modifications, that you identified while responding to this generic letter. Efforts to implement the identified actions should be initiated no later than the first refueling outage starting after April 1, 2006. All actions should be completed by December 31, 2007. Provide justification for not implementing the identified actions during the first refueling outage starting after April 1, 2006.
If all corrective actions will not be completed by December 31, 2007, describe how the regulatory requirements discussed in the Applicable Regulatory Requirements section will be met until the corrective actions are completed.
Based on the results from debris generation and transport analyses identified and described below, modifications to the existing debris screens will be required to meet the applicable Regulatory Requirements discussed in the generic letter. The strainer design (surface area, perforation size, and layout) and final head-loss will be determined by the strainer vendor. Based on scoping evaluations, modifications are expected to consist of new safety injection sump strainers with a surface area of approximately 4250 (without thin bed effect (TBE)) square feet and greater than 10,000 (with TBE) square feet (based on a metal encapsulated fiberglass insulation (MEI) zone of influence (ZOI) of 17.OD as discussed in 2(c) below) with 0.125 (1/8) inch (diameter) perforations, or smaller. This area includes 125 square feet of sacrificial surface area to W3F1 -2005-0063 Page 2 of 12 for tape, labels, etc. The new strainers are expected to occupy the space above the existing safety injection sump as well as areas around and near the existing sump.
Plant modifications to install new sump strainers will be implemented during refueling outage 14, scheduled in the fall of 2006..
(c) A description of the methodology that was used to perform the analysis of the susceptibility of the ECCS and CSS recirculation functions to the adverse effects of post-accident debris blockage and operation with debris-laden fluids. The submittal may reference a guidance document (e.g., Regulatory Guide (RG) 1.82, Revision 3, industry guidance) or other methodology previously submitted to the NRC. (The submittal may also reference the response to Item I of the Requested Information described above. The documents to be submitted or referenced should include the results of any supporting containment walkdown surveillance performed to identify potential debris sources and other pertinent containment characteristics.)
The analysis of the susceptibility of the ECCS and CSS recirculation functions to the adverse effects of post-accident debris blockage was performed using methodology in the Nuclear Energy Institute (NEI) guidance document NEI 04-07 (Reference 1), as modified by the NRC's safety evaluation report (SER) for NEI 04-07 (Reference 2).
Containment walkdowns to support the analysis of debris blockage were performed using the guidelines provided in NEI 02-01 (Reference 3).
The reactor coolant system (RCS) at W-3 is arranged as two closed loops (designated as loops 1 and 2). Each loop consists of one steam generator (SG), two reactor coolant pumps (RCPs), and the associated RCS piping, and is located within its own cavity.
The two loops are nearly identical with the exception that loop 1 includes the majority of the pressurizer surge line piping. The pressurizer is outside the cavities of both loops.
Baseline Break Selection Several break locations were selected for evaluation following the guidance of RG 1.82, Revision 3. Breaks in feedwater and/or main steam system piping are not considered because they do not require the ECCS and/or CSS to operate in recirculation mode. In accordance with NEI 04-07, small-bore piping (2" nominal diameter and less) is not considered as the impact is bounded by the larger breaks. The selected breaks are as follows:
Break SI is at the hot leg at the inlet to SG 1. Because the hot leg is the largest line in containment, a break at this location produces the largest ZOI with the most debris. SG 1 and RCPs 1A/lB are within the ZOI.
Break S2 is at the SG 1 hot leg piping at the Reactor Pressure Vessel (RPV) connection. A break at this location primarily affects the insulation within the reactor cavity.
Break S3 is at the hot leg at the inlet to SG 2. This break is the mirror image of break SI and is selected to give debris loading for other transport paths.
to W3FI-2005-0063 Page 3 of 12 Break S4 is at the pressurizer surge line connection to the RCS hot leg. This break was selected because the pressurizer surge line has a larger inner diameter than a 14-inch Schedule 160 line and is in approximately the same location as the bounding break (break SI). A break at this location produces a more limiting debris load than a break equivalent to a 14-inch Schedule 160 break at any location on the RCS piping.
Break S5 is a break in the cold leg suction line connection to RCP 1A. This break is selected because it has a more direct flow path to the safety injection sump and therefore could result in the transport of a greater amount of debris than break S1.
Break S6 is a break in the cold leg suction line connection to RCP 2B. This break is selected because it has a more direct flow path to the safety injection sump and therefore could result in the transport of a greater amount of debris than break S3.
Break S7 is at the pressurizer surge line at the connection to the pressurizer. A break is postulated here because it has the most direct flow path to the safety injection sump.
Debris Generation Insulation: With the exception of MEI and Microtherm insulation, insulation debris types are quantified using the ZOI radius specified by the SER in Table 3-2. For the MEI, a ZOI radius equivalent to that of unjacketed Nukon (17.OD) was conservatively assumed; however, a ZOI of 2.0D for MEI was also evaluated based on the fact that the jacketing is equivalent to that for reflective metal insulation (RMI). For Microtherm, a ZOI radius equivalent to that of Min-K insulation (28.6D) was conservatively assumed. For the piping insulation debris, a 3D model was used to identify piping within the ZOI and calculate the impacted insulation volume. For equipment insulation, the sections of insulation within the ZOI were determined based on dimensioned insulation and plant layout drawings.
Coatings: Qualified coating debris was quantified using the ZOI radius of 10.OD, as specified by the SER in Section 3.4.2.1. The concrete and structural steel coatings within the ZOI were determined based on dimensioned plant drawings. For the purpose of determining impacted coating volumes, the coated surfaces within the ZOI are assumed to have the maximum of the possible thickness values as delineated by the specifications. In accordance with NEI 04-07 and the SER, all unqualified coatings are considered to fail regardless of their location within containment. Similarly, all qualified coatings that have been identified as being degraded are considered to fail regardless of their location within containment.
Foreign Material: The quantity and type of foreign material inside containment was based on a walkdown performed for W-3. The foreign material included labels, signs, placards, etc. All foreign material was assumed to transport to the safety injection sump.
Latent Debris: A latent debris walkdown was performed in accordance with the NEI/SER guidelines in Section 3.5. Using cloths, samples were collected from the various surfaces at different floor elevations. Samples from each of the following surfaces were taken:
to W3FI-2005-0063 Page 4 of 12 Horizontal concrete surfaces (floors)
Vertical concrete surfaces (walls)
Containment liner (vertical)
Cable trays (vertical)
Cable trays (horizontal)
Horizontal equipment surfaces (heat exchangers, air coolers, etc.)
Vertical equipment surfaces (SG, air coolers, pressurizer, etc.)
Horizontal heating, ventilation, and air conditioning (HVAC) duct surfaces Vertical HVAC duct surfaces Horizontal piping surfaces Vertical piping surfaces (pipes running vertically)
The net weight differences of the cloths between the pre-sample and post-sample weight were used to statistically extrapolate the amount of latent debris for the entire containment.
Entergy is evaluating additional refinements that could possibly be utilized in the future for margin recovery or revisions to the calculations. An example would be to add jacketing to certain insulation types. Another example would be a reduction in the ZOI for coatings which would require a technical justification that could include specific coating debris generation testing prior to implementation.
Debris Transport The transport of the debris from the break location to the safety injection sump screen is evaluated using the methods outlined in Section 3.6 of NEI 04-07 with the enhancements recommended in the SER. The means of transport considered were blowdown, washdown, pool fill, and recirculation for all types of debris. The recirculation transport analysis was performed using computational fluid dynamics (CFD) models developed using the computer program FLUENT. Outputs of the CFD analysis include global (entire containment) and local (near safety injection sump pit) velocity contours, turbulent kinetic energy (TKE) contours, path lines and flow distributions for various scenarios.
Nukon fibrous debris was characterized into four debris size categories based on the interpretation of the air-jet impact testing (AJIT) test data. The NEI small fines category was subdivided into fines (8%) and small pieces (25%) and the NEI large category was subdivided into large pieces (32%) and intact debris (35%). The MEI was assumed to be small fines (100%). All fines were considered to transport to the screen. Based on the comparison of recirculation pool velocities determined using CFD analysis with incipient debris tumbling velocities provided in NUREG/CR-6772, the small pieces and large pieces do not transport to the screen in bulk, but are subject to 90% erosion and subsequent transport as fines.
The containment spray and submergence generated fibrous debris is modeled as fines and 100% transports to the screen.
to W3F1I-2005-0063 Page 5 of 12 The particulate and coating debris was modeled as fines and 100% transports to the screen.
The debris transport phenomena due to the blowdown, washdown, pool fill-up, and recirculation transport modes were summarized using debris transport logic trees consistent with the Drywell Debris Transport Study (DDTS) documented in NUREG/CR-6369. The debris transport logic trees consider the effect of dislocation, hold up on the floor or other structures, deposition in active or inactive pools, lift over curbs, and erosion of debris.
Miscellaneous debris (tape, labels, etc.) is not included in the debris load, but is considered in the procurement specification for the screen design as a sacrificial area.
The following is a summary of the overall transport fractions for the debris types:
Debris Type Overall Transport Fraction Transco RMI 0.75 Nukon Fiber (within ZOI) 0.59 Nukon Fiber (CS/Submerged Generated) 1.00 MEl (Fiberglass) 1.00 Microtherm 1.00 Min-K 1.00 Coatings 1.00 Latent Debris 1.00 Foreign Material 1.00 Strainer Head-Loss As noted earlier, the final strainer head-loss analysis will be performed by the strainer vendor. The debris bed head-loss and net-positive suction head (NPSH) margin analysis for the scoping evaluation is documented in Reference 6. The analysis determines that the existing safety injection sump screen cannot accommodate the debris inventory transported to the sump screen based on the head-loss through the debris bed, which would form during recirculation. In this scoping evaluation, the head-loss across the debris bed is determined separately for fiber and particulate debris and for RMI debris. The head-loss through a fiber/particulate debris bed was determined using the head-loss correlation developed in NUREG/CR-6224 while the RMI debris bed head-loss is determined using the correlation recommended in NUREG/CR-6808. The total head-loss across the safety injection sump strainer is equal to the sum of the fiber/particulate debris bed head-loss, the RMI debris bed head-loss and the clean strainer head-loss. The qualified and unqualified coatings at W-3 are both epoxy and inorganic zinc. In the determination of debris bed head-loss, the coatings were assumed to be epoxy because epoxy conservatively results in a greater head-loss than inorganic zinc and alkyds.
In Reference 6, strainer size estimates from the scoping evaluation are greater than 10,000 (with TBE) and approximately 4,250 (without TBE) sq. ft. The strainer size estimates are provided based on the case where high-pressure safety injection (HPSI) pump A/B is taking suction from safety injection sump penetration 32 (most limiting to W3Fl-2005-0063 Page 6 of 12 case). The estimates are also based on the total allowable head-loss with no NPSH margin retention. The allowable head-loss across the safety injection sump strainer, 1.04 feet, is documented in Reference 6.
Downstream Effects For downstream effects, see paragraphs (d)(v) and (d)(vi).
(d) The submittal should include, at a minimum, the following information:
(d)(i)
The minimum available NPSH margin for the ECCS and CSS pumps with an unblocked sump screen.
The minimum available NPSH margin for the ECCS HPSI pumps in the recirculation mode at ECCS switchover to safety injection sump recirculation, not including the clean strainer head-loss, is 1.04 feet. The minimum available NPSH margin for the CS pumps in the containment spray recirculation mode at CS switchover to safety injection sump recirculation, not including the clean strainer head-loss, is 6.05 feet (Reference 6). The clean strainer head-loss is small (<0.1 feet based on experience). As noted earlier, the final values will be determined by the sump strainer vendor.
(d)(ii) The submerged area of the sump screen at this time and the percent of submergence of the sump screen (i.e., partial or full) at the time of the switchover to sump recirculation.
The procurement specification requires the strainers to be fully submerged (submergence of 100%, Reference 8) for both large and small break LOCAs.
(d)(iii) The maximum head-loss postulated from debris accumulation on the submerged sump screen, and a description of the primary constituents of the debris bed that result in this head-loss. In addition to debris generated by jet forces from the pipe rupture, debris created by the resulting containment environment (thermal and chemical) and CSS washdown should be considered in the analyses. Examples of this type of debris are disbanded coatings in the form of chips and particulates and chemical precipitants caused by chemical reactions in the pool.
The maximum postulated head-loss from debris accumulation on the submerged safety injection sump strainer is specified to be 0.84 feet of water or less. The primary constituents of the debris bed are as follows (Reference 6):
RMI (fines) 0.0 sq. ft.
Granular Insulation (Min-K, Microtherm) 4.6 cu. ft.
Fibers (17.OD) 2240 cu. ft.
Fibers (17.0D with 2.OD for MEl) 1459 cu. ft.
Particulate 171.6 cu. ft.
Miscellaneous materials (tape, labels, etc.)
151 sq. ft.
Latent Debris*
250 Ibm to W3Fl-2005-0063 Page 7 of 12
- 250 Ibm of latent debris (dust and lint) is used in the strainer design specifications.
Based on the W-3 latent debris walkdown, the calculated latent debris is 238.9 Ibm (Reference 4).
The procurement specification is requesting the vendors to size the strainer based on fiber debris of 17.0D and also for 2.00 for MEL. Based on the bids received from the sump strainer vendors, Entergy will decide whether to use the 17.0D or 2.OD for MEI for fiber loading.
Sump strainer suppliers are currently developing plans and schedules to quantify the additional head-loss associated with Chemical Debris (Reference 11). Entergy plans to evaluate the adequacy of the strainer design and will incorporate chemical effects once the test results to quantify chemical debris effect on head-loss have been published. At the same time, an additional evaluation will be performed to determine the impact of the sump pH, spray duration, and the increased temperature profile on the head-loss due to chemical effects.
Margins exist that could be available to address head-loss increases due to chemical effects. For example, the new sump screen design provides an inherent head-loss margin of approximately 23% based on the maximum head allowed in the procurement specification versus the NPSH available. As noted earlier, Entergy plans to account for chemical effects during the screen design process.
(d)(iv) The basis for concluding that the water inventory required to ensure adequate ECCS or CSS recirculation would not be held up or diverted by debris blockage at choke-points in containment recirculation sump return flowpaths.
In general, the containment floors are clear of major obstructions that could prevent flow from reaching the safety injection sump strainers. The configuration of the containment basement elevation is conducive to directing flow to the safety injection sump. The entire basement elevation of the containment building serves as an area for collection of water introduced to the containment following a LOCA. The basement floor elevation is essentially an open area except for the primary reactor shield wall, the walls and supports for the loop compartments (D-rings), and the refueling cavity. The flow paths from the upper levels of containment to the lower levels are relatively free, i.e., open stairways and/or floor grating. The D-rings contain the RCPs and SGs. These vaults have large openings that allow water to spill to the containment basement elevation. Other hold-up volumes not connected to the safety injection sump have been included in the minimum water level calculation. The refueling canal drains through two 6-inch pipes to the containment floor and a 4-inch line to the containment sump. The 6 inch pipes will remain unobstructed and therefore, a credible path to the containment pool exists and there is no hold up of inventory in the refueling canal. Furthermore, the path from the refueling canal to the containment floor/sump does not bypass the safety injection sump strainer.
(d)(v) The basis for concluding that inadequate core or containment cooling would not result due to debris blockage at flow restrictions in the ECCS and CSS to W3F1 -2005-0063 Page 8 of 12 flowpaths downstream of the sump screen, (e.g., a HPSI throttle valve, pump bearings and seals, fuel assembly inlet debris screen, or containment spray nozzles). The discussion should consider the adequacy of the sump screen's mesh spacing and state the basis for concluding that adverse gaps or breaches are not present on the screen surface.
The flow paths downstream of the containment safety injection sump were analyzed to determine the potential for blockage due to debris passing through the sump strainer (Reference 7). The acceptance criteria were based on WCAP-16406-P (Reference 10).
These evaluations were done for components in the recirculation flow paths including, but not limited to, throttle valves, flow orifices, spray nozzles, pumps, heat exchangers, and valves. The methodology employed in this evaluation was based upon input obtained from a review of the recirculation flow path shown on piping and instrument diagram drawings and plant procedures. The steps used in obtaining the flow clearance were as follows:
Determine the maximum characteristic dimension of the debris (clearance through the safety injection sump strainer).
Identify the recirculation flow paths.
Identify the components in the recirculation flow paths.
Review the vendor documents (drawings and/or manuals) for the components to obtain flow clearance dimensions.
Determine blockage potential through a comparison of the flow clearance through the component with the flow clearance through the safety injection sump strainer.
Identify the components that require a detailed evaluation and investigation of the effects of debris on their capability to perform their designated safety function.
The results of the preliminary evaluation for flow clearances showed that some components require additional evaluation for long-term wear. As discussed in d(vi),
the long term downstream evaluations are in progress. The resolution and corrective actions for the downstream components will be performed with the long-term evaluations.
The procurement specification requires the new strainer design to ensure that gaps at mating surfaces within the strainer assembly and between the strainer and the supporting surface do not have gaps in excess of the strainer perforation size.
(d)(vi) Verification that close-tolerance subcomponents in pumps, valves and other ECCS and CSS components are not susceptible to plugging or excessive wear due to extended post-accident operation with debris-laden fluids.
Verification of debris blockage of downstream components is described in (d)(v). As noted earlier, verification of downstream components for long-term wear is in progress, and the final results will be reported to the NRC by December 15, 2005.
to W3F1 -2005-0063 Page 9 of 12 The long-term downstream effects evaluation is in progress using the methodology and acceptance criteria presented in WCAP-16406-P (Reference 10). Where excessive wear is found using this methodology, a refined approach using methods such as those described in Department of Energy, Centrifugal Slurry Pump Wear and Hydraulic Studies conducted from October 1982 to December 1987 (Reference
- 13) would be utilized.
For the long-term wear evaluations, the debris types, quantities and properties of debris are obtained from the debris transport and head-loss calculations (Reference
- 6) and the sump screen procurement specification (Reference 8).
(d)(vii) Verification that the strength of the trash racks is adequate to protect the debris screens from missiles and other large debris. The submittal should also provide verification that the trash racks and sump screens are capable of withstanding the loads imposed by expanding jets, missiles, the accumulation of debris, and pressure differentials caused by post-loss-of-coolant accident (LOCA) blockage under predicted flow conditions.
The safety injection sump is located outside the missile barriers and any zones of influence of high energy line breaks. Therefore, the strainers are not subject to loads from missiles or expanding jets. The need for trash racks would be determined during the detailed strainer design phase. The procurement specification requires that the strainers are designed to withstand the loads imposed by the accumulation of debris and pressure differentials under predicted flow conditions as specified in the design requirements, as well as seismically generated loads (Reference 8).
(d)(viii) If an active approach (e.g., backflushing, powered screens) is selected in lieu of or in addition to a passive approach to mitigate the effects of the debris blockage, describe the approach and associated analyses.
The strainers are expected to be of a passive design.
(e) A general description of and planned schedule for any changes to the plant licensing bases resulting from any analysis or plant modifications made to ensure compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of this generic letter. Any licensing actions or exemption requests needed to support changes to the plant licensing basis should be included.
Changes to the plant licensing bases are performed during the modification process via 10CFR50.59. Depending on the results received from the strainer vendor, there is a potential for affecting the W-3 Technical Specifications. Entergy will notify the NRC by December 15, 2005, should a technical specification be necessary.
(f) A description of the existing or planned programmatic controls that will ensure that potential sources of debris introduced into containment (e.g., insulations, signs, coatings, and foreign materials) will be assessed for potential adverse to W3Fl-2005-0063 Page 10 of 12 effects on the ECCS and CSS recirculation functions. Addressees may reference their responses to GL 98-04, "Potential for Degradation of the ECCS and the CSS after LOCA Because of Construction and Protective Coating Deficiencies and Foreign Material in Containment," to the extent that their responses address these specific foreign material control issues.
Entergy realizes that control of potential debris sources inside of containment is very important and that debris sources that are introduced to containment need to be identified and assessed. Potential debris sources can be generally categorized into the following general areas: insulation, coatings (both qualified and unqualified),
miscellaneous sources (labels, tags, tape, etc.), and dirt/dust. Entergy currently implements the following controls for these potential sources of debris.
Insulation used inside of containment is identified on site drawings. In addition, insulation walkdowns were performed to support GL 2004-02. Entergy will ensure that as part of the modification process, insulation materials that are introduced to containment are identified and evaluated to determine if they could affect sump performance or lead to downstream equipment degradation.
The majority of the coatings inside of containment were procured and applied as qualified coatings. Qualified coatings are controlled under site procedures. In addition, the debris generation calculation discussed above, includes margin for potential detachment or failure of limited quantities of qualified coatings. Entergy will repair or assess damaged qualified coatings to ensure that the quantities of failed coatings in the debris generation calculation are not exceeded.
Unqualified coatings have been identified by location, surface area, and thickness. The majority of unqualified coatings inside of containment are component Original Equipment Manufacturer coatings. New or replacement equipment is evaluated for the potential of unqualified coatings. Entergy will ensure that unqualified coatings introduced to containment are identified. Entergy will implement a program to track the unqualified coatings to ensure that the quantity of unqualified coatings in the debris generation calculation is not exceeded.
Walkdowns in support of resolution of GL 2004-02 identified and quantified miscellaneous potential sources of debris (tags, labels, tape, etc.) inside of containment. The modification process requires that materials introduced to containment be identified and evaluated for potential impact to the sump and equipment as part of the design process. Administrative procedures control the types of tags and labels that can be used inside of containment. During recent outages, efforts have been taken to reduce the quantities of these miscellaneous debris sources inside of containment. Entergy will implement a program to track the tags and labels that remain inside containment to ensure that the amount does not exceed the sacrificial area provided in the design.
At the end of an outage, a formal containment close-out surveillance procedure is performed. The close-out is performed to ensure that materials do not affect the ECCS including the sump. Items not removed require a documented evaluation to provide the basis for concluding that the item remaining in containment is acceptable. As part of to W3F1 -2005-0063 Page 11 of 12 containment close-out, each ECCS train containment sump and sump screens are inspected for damage or debris. Also, refueling canal drains are verified not to be obstructed and that there are no potential debris sources in the refueling canal area that could obstruct the drains.
As discussed above, as part of the containment walkdowns used to identify potential debris sources, measurements were taken to conservatively estimate the amount of latent dirt and dust inside of containment. These measurements were taken at a point during the respective refueling outage where the level of dirt and dust would be much higher than during normal power operation. Subsequent to the measurements being taken but prior to unit startup, extensive cleaning was performed. These cleaning activities are consistent with normal housekeeping practices and associated administrative requirements. To provide an additional level of conservatism, the actual dirt and dust quantities assumed in the analysis are much greater than the values.
determined from the measurements. In order to ensure that the analysis remains bounding, Entergy intends to perform these types of measurements every third refueling outage, although this frequency may be relaxed following the first measurement.
Assuming the results indicate that the housekeeping practices provide an adequate level of cleanliness, the plant may choose to relax this frequency after the first measurements.
References
- 1) NEI Document NEI 04-07, Rev. 0, Dated December 2004, Pressurized Water Reactor Sump Performance Evaluation Methodology
- 2) Safety Evaluation by The Office of Nuclear Reactor Regulation Related to NRC Generic Letter 2004-02, NEI Guidance Report, Pressurized Water Reactor Sump Performance Evaluation Methodology
- 4) Sargent & Lundy LLC Calculation 2004-07780, Debris Generation Due to LOCA within Containment for Resolution of GSI 191
- 5) Sargent & Lundy LLC Document No. 2003-10420, Rev. 0, dated January 19, 2004, Walkdown Report for Evaluating Debris Sources Inside Waterford-3 Containment for Resolution of GSI 191
- 6) Sargent & Lundy LLC Calculation No. 2005-05500, Post-LOCA Debris Transport, Head-Loss Across Safety Injection Sump Screen, and NPSH Evaluation for Resolution of GSI-191
- 7) Sargent & Lundy LLC Document No. 2005-02820, Rev. 0, dated August 18, 2005, GSI-191 Downstream Effects - Flow Clearances
- 8) Sargent & Lundy LLC Specification No. W-6090, Rev. 0, dated August 22, 2005, Technical Specification for Containment Sump Strainers to W3F1 -2005-0063 Page 12 of 12
- 9) Sargent & Lundy LLC Document No. 2005-8760, GSI-191, Chemical Effect Evaluation
- 10) Westinghouse Evaluation WCAP-16406-P, dated June 2005, Evaluation of Downstream Sump Debris Effects in Support of GSI-191
- 11) Vendor comment during NRC Public Meeting on June 30, 2005
- 12) Test Plan: Characterization of Chemical and Corrosion Effects Potentially Occurring Inside a PWR Containment Following a LOCA, Revision 13, dated July 20, 2005
- 13) Department of Energy, Centrifugal Slurry Pump Wear and Hydraulic Studies conducted from October 1982 to December 1987 W3FI-2005-0063 List of Regulatory Commitments to W3F1 -2005-0063 Page 1 of 2 List of Regulatory Commitments The following table identifies those actions committed to by Entergy in this document. Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments.
TYPE (Check One)
SCHEDULED ONE-COMPLETION TIME CONTINUING DATE COMMITMENT ACTION COMPLIANCE (If Required)
The results of the downstream effects X
December 15, 2005 evaluation for long-term wear will be submitted to the NRC.
W-3 will meet the applicable Regulatory X
December 20, 2006 Requirements discussed in the generic letter.
W-3 plant modifications to install new X
December 20, 2006 sump strainers will be implemented during the fall 2006 refueling outage.
Entergy plans to evaluate the adequacy X
December 20, 2006 of the strainer design and will incorporate chemical effects once the tests results to quantify chemical debris effect on head-loss have been published. At the same time, an additional evaluation will be performed to determine the impact of the sump pH, spray duration, and the increased temperature profile on the head-loss due to chemical effects.
The resolution and corrective actions for X
December 15, 2005 the downstream components will be performed with the long-term evaluations.
Entergy will notify the NRC should a X
December 15, 2005 technical specification be necessary.
Entergy will ensure that as part of the X
December 20, 2006 modification process, insulation materials that are introduced to containment are identified and evaluated to determine if they could affect sump performance or lead to downstream equipment degradation.
to W3F1 -2005-0063 Page 2 of 2 Entergy will repair or assess damaged X
December 20, 2006 qualified coatings to ensure that the quantities of failed coatings in the debris generation calculation are not exceeded.
Entergy will ensure that unqualified X
December 20, 2006 coatings introduced to containment are identified.
Entergy will implement a program to X
December 20, 2006 track the unqualified coatings to ensure that the quantity of unqualified coatings in the debris generation calculation is not exceeded.
Entergy will implement a program to X
December 20, 2006 track the tags and labels that remain inside containment to ensure that the amount does not exceed the sacrificial area provided in the design.
In order to ensure that the analysis X
Recurring every third remains bounding, Entergy intends to refueling outage perform these types of measurements (latent debris) every third refueling outage, although this frequency may be relaxed following the first measurement.