ML20235A632
| ML20235A632 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 09/16/1987 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8709230363 | |
| Download: ML20235A632 (17) | |
Text
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TENNESSEE VALLEY AUTHORITY CHA1TANOOGA, TENNESSEE 374o1 SN 157B Lookout Place SEP 161987 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 j
Gentlemen:
In the Matter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAH NUCLEAR PLANT (SQN) - CONTAINMENT COATINGS In TVA/NRC technical presentation meetings held August 19-20, 1987, at SQN, 3
TVA agreed to provide a submittal describing SQN containment coatings issues and TVA's resolution to those issues.
Accordingly, this information is provided in enclosures 1 and 2 and updates the information regarding containment coatings provided in Volume 2 of the SQN Nuclear Performance Plan (NPP). The issues and resolution methodology discussed are generic to both units 1 and 2, although details provided in the enclosures are unit 2 specific. provides a description of recent issues related to containment coatings at SQN and the corrective actions taken to resolve those issues.
Additionally, the licensing basis is updated for SQN containment coatings and the containment sump. Appropriate revision to the SQN Final Safety Analysis Report (FSAR) will be made in the next regular update scheduled for April 1988. The information provided also clarifies the apparent inconsistency between sections 15.3 and 15.4 of Volume 2 of the SQN NPP by describing the screen arrangement that prevents transport of possible failed coatings from two accumulator rooms to the sump by a recently installed drain lines. provides an executive summary for the supporting Westinghouse transport study referenced in enclosure 1. lists the commitment made in this letter.
If you have any questions, please telephone M. R. Harding at 615/870-6422.
Very truly yours, TENNES EE VALLEY AUTHORITY R. Gridley, D ector Nuclear Safety and Licensing Enclosures cc: See page 2
/}00l P
.-. opportunity Employer
c
. U.S. Nuclear Regulatory Commission SEP 161987 cc (Enclosures):
Mr. G. G. Zech, Assistant Director for Inspection Programs Office of Special Projects U.S. Nuclear Regulatory Commission 101 Mariettu Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. J. A. Zwolinski, Assistant Director for Projects Division of TVA Projects Office of Special Projects U.S. Nuclear Regulatory Commission 4350 East-West Highway EWW 322 Bethesda, Maryland 20814 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379
ENCLOSURE 1 SEQUOYAH NUCLEAR PLANT (SQN)
CONTAINMENT COATINGS ISSUES AND CORRECTIVE ACTIONS EXECUTIVE
SUMMARY
This submittal describes issues related to coatings inside containment at SQN, relates these issues to the licensing basis of the plant, and describes the corrective actions that TVA has implemented. TVA identified three basic issues with containment coatings:
programmatic, physical, and basis for operability.
Steps have been taken to address each issue with immediate corrective action and the establishment of a long-term program.
The coatings maintenance program has been revised and strengthened.
Coatings have been physically removed, repaired or have had barriers erected to prevent transport to the containment sump consistent with the operability basis. The operability basis has been reestablished with a physical transport study.
The licensing bases for containment coatings and the containment sump are updated by this submittal. As a result of the efforts described in this submittal, TVA believes that all of the SQN containment coatings issues have been resolved.
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I. PURPOSE This submittal describes issues related to containment coatings at SQN, relates these issues to the original and updated licensing basis of the plant, and describes the corrective actions TVA has implemented.
There are three basic issues that will be discussed in more detail in the remainder of the submittal:
1.
pro 5rammatic--lack of a coatings maintenance program and inadequate control of unqualified coatings inside containment after construction was complete.
2.
physical--delamination of coatings inside containment and discovery that some coatings were no longer considered to be qualified.
3.
Operability basis--failure to establish a mechanistic basis for the acceptability of an amount of containment coatings that may not be qualified.
II.
ORIGINAL LICENSING BASIS A.
Coatings SQN Final Safety Analysis Report (FSAR) section 6.2.1.6 describes the original licensing basis for the coatings inside containment.
It states that "Except for insignificant amounts, coating products and systems used will have been fully prequalified for normal operating service and DBA accident conditions in accordance with ANSI N5.9-1967 and ANSI N101.2-1972." The "DBA accident conditions" were those associated with a large loss of cooling accident (LOCA).
This was confirmed by the NRC staff in their original SER for SQN (NUREG-0011) that stated in section 6.1.2 ".
. that the organic coating materials used in the containment have been qualified under conditions up to and including the design basis loss-of-coolant accident and are acceptable." FSAR section 6.2.1.6 also states that
" Unidentified coatings will be accounted for.
Should the quantity of unidentified coatings exceed a negligible fraction of the containment interior surfaces, that amount will be reduced to an acceptable fraction through removal and application of satisfactory coatings."
B.
Containment Sump The original licensing basis for the containment recirculation sump is described in SQN FSAR section 6.2.2.2, and SQN sump design details were provided in TVA's response to NRC question 6.6.
The sump has a J
6-inch trash curb around the base of 1/4-inch wire mesh screens that j
slope upward and outward from the sump to prevent debris from entering that could affect the operation of the containment Spray
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System.
The NRC SER Supplement 2 states in section 6.3.3 that the l
" design acceptably avoids the use of materials in the containment L___________________
which would ba likely to produce smsll-sized dabris in significant quantities.
" that could " pass through the fine screens in the sump " The SQN containment sump was designed and constructed before issuance of NRC Regulatory Guide (RG) 1.82, revision 0, and only partially conforms to its requirements. However, out-of-plant scale model tests of sump performance were conducted by TVA incorporating the 50-percent partial screen blockage recommended by RG 1.82.
Based on these tests and extensive review by the NRC staff. TVA modified the sump and containment crane wall in response to vortexing and net positive suction head (NPSH) issues. A complete study to demonstrate the acceptability of the sump design was submitted by letter from J. E. Gilleland, TVA, to S. A. Varga, NRC, dated November 7, 1978. The I
NRC SER Supplement 1 states in section 6.3.4 that "the staff finds the present recirculation sump design to be acceptable, and believes that the applicant has demonstrated reasonable assurance that it will perform as expected following a LOCA."
III. DETAILED DESCRIPTI'ON OF ISSUES A.
Programmatic During a routine reviev of maintenance work requests by TVA in early 1986, a discrepancy was found between coating specifications and design drawings for items that were to be installed inside primary containment (Coating Service Level I).
TVA initiated an investigation and determined that, contrary to FSAR commitments, the
" Uncontrolled Coatings Log" from the construction phase had not been
. maintained after operating license issuance.
As a result, during modification and maintenance activities, uncontrolled, vendor-coated items had been installed inside containment without being tracked or accounted for in the log.
In addition, coatings inside containment were not subject to a program of periodic inspection and maintenance.
B.
Physical At approximately the same time TVA conducted an investigation of an employee concern regarding the integrity of certain coatings inside containment. TVA identified areas of damaged and deteriorated coating and recommended that repairs be made or safety evaluations performed before reactor startup. This report also recommended further inspections to verify the integrity of all containment coatings.
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A costing surysy procedura was written end c walkdown was performed in order to identify all areas of coating failure and to reestablish the uncontrolled coatings log.
In addition, a review of vendor l
documentation determined that some large vendor-coated components l
that had been tested to and had passed earlier design basis accident (DBA) qualification procedures (1968), now were known to fail when l
tested to current qualification procedures (ANSI N101.2-1972). These components, whose coatings were now considered to be unqualified, included the pressurizer relief tank (pRT), reactor coolant pump (RCp) motors, and the upper ice condenser doors.
Additional coating inspection raised concerns regarding inorganic zine (IOZ) primer on the containment liner plate, containment dome, and structural steel. Apparently, the IOZ was originally applied too thin (less than 2.5 mils).
In an attempt to correct the low thickness, additional coats were applied incorrectly. The result was excessive thickness, dry powdery overspray, and poor cohesion. The adverse condition was compounded in some areas with the application of an epoxy topcoat.
proper adhesion was not obtained, and random delamination resulted. The failure was due to lack of cohesion within the IOZ primer.
As discussed previously in section II.A. the original DBA for coating environmental qualification was a large LOCA.
Since that time, it has been determined that the LOCA containment temperature profile does not bound the profile following a main steam line break (MSLB).
2 of Thissituationresultsinapgroximatelyanadditional12,000ft topcoated steel and 7,500 ft of concrete inside the containment not being qualified for an MSLB.
C.
Operability Basis TVA maintained an issued calculation that established limits on the amount of containment coatings in the upper cnd lower compartments that could be tolerated to fail after a DBA.
This calculation was reviewed during the recent TVA calculations review effort and was determined to be unacceptable due to a number of assumptions that could not be verified.
IV.
CORRECTIVE ACTION AND STATUS A.
programmatic The construction coating specifications were intended to provide requirements for the initial construction work and did not establish a formalized program of periodic inspection and maintenance, which is essential during plant operation.
Corrective action that has been accomplished includes an extensive revision of the TVA General Construction Coating Specification to incorporate operating plant 4_
4 conditions and requirements.
Responsibilities, qualifications, and training requirements for coating work personnel were redefined. The Division of Nuclear Engineering was established as the lead organization responsible for all coating work.
A new site-specific standard practice was issued, and the applicable maintenance instruction was revised in order to adequately implement the upgraded Nuclear Coatings program as defined in the new construction specification.
preventative maintenance procedures requiring periodic surveillance inspections were issued.
A walkdown was performed to reestablish the baseline for the uncontrolled coatings log, and provisions for upkeep of the log were accomplished by a revision of maintenance and modification procedures.
B.
physical Extensive rework and repair were performed on coatings. As a result of the improved inspection and maintenance program, approximately 2
4,300 ft of cracking and delaminating concrete coating--inner crane wall floor and pressurizer / steam generator enclosures--was removed and replaced with a superior system.
In order to reduce the amount of coating now considered to be unqualified on vendor-supplied components, approximately 1,730 ft2 of unqualified coating was removed and the areas recoated with an approved, qualified epoxy system.
This included 1.470 ft2 on the pRT in the lower 2
compartment and 260 ft on the ice condenser doors in the upper compartment. Acceptance criteria were established for the IOZ/ epoxy system that was prone to delamination due to misapplication.
Approximately 2,700 ft2 of delsminating and out-of-specification IOZ/ epoxy was removed from the upper compartment liner plate and dome by mechanical abrading and scraping. The improperly applied IOZ that was not topcoated was determined not to be detrimental to performance of the required accident mitigation systems because the failure mode of the excessive zine is expected to be in the form of a fine powder with no potential for screen, core, or component blockage.
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addition, 250 ft of delaminating IOZ/ epoxy on structural steel in the lower compartment was removed and recoated.
In addition to the physical repairs to the containment coatings just described. TVA has completed erection of barriers of 40-mil mesh screens to prevent the transport of potential failed coatings from certain components to the recirculation sump.
Screened platforms were installed underneath each of the four RCp motors.
Screens were installed over the inlets of the two recently-added drains from accumulator rooms outside the crane wall.
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Thszo berriers ara designed to prevent the passage of any debris from potential failed coatings larger than 40 mils from the accumulator rooms to the containment sump.
Table I-1 presents a summary of the total surface areas, thicknesses, and locations of those coatings that will exist inside containment at restart and that are considered environmentally unqualified for the design basis events listed.
The physical transport study performed by Westinghouse and described in the following uection explicitly considers only that portion of the total amount of unqualified coatings that can be potentially transported to the containment sump.
C.
Operability Basis The basis for operability of the plant with the previously described amounts of coatings that could fail in a DBA was determined by a physical transport study performed by Westinghouse.
The Westinghouse study provides the basis for acceptability of present containment coatings for restart and will later be used as a basis to reestablish limits for the uncontrolled coatings los described in section IV. A.
Although a description of the transport study and its conclusions are provided in enclosure 2 of this submittal, it will be summarized here briefly.
The study examined the effects on the sump screen and the reactor core of blockage because of coatings and insulation debris for LOCA and MSLB. The screen was evaluated for NPSH effects and the core for heatup effects. The methodology focused on a near-sump region of influence based on postaccident flow fields and addressed potential effects caused by the return of containment spray flow through the refueling canal drains and by flow from the LOCA short-term blowdown. For a LOCA, the flow field is caused by the residual heat removal (RHR) and containment spray pumps taking suction from the sump. For an MSLB, the flow field is induced by the containment spray pumps and by the centrifugal charging pumps taking suction from the RHR pumps to supply reactor coolant system makeup and RCP seal injection. Both reflective metallic and fibrous NUKON insulation were included in the study as well as potentially failed coatings. The Westinghouse study concluded that the debris that could potentially fail in a DBA and be transported to the containment recirculation sump would not unacceptably degrade the capabilities of
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the required accident mitigation systems.
In addition. TVA's Norris Laboratory evaluated the propensity for I
vortexing above the sump for the DBAs and amounts of screen blockage postulated in the Westinghouse study and concluded that the sump i
performance was acceptable.
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_V. UPDATED LICENSING BASIS A.
Coatings This submittal' describes the updated licensing basis for the coatings inside containment. Specifically, containment coatings will be environmentally qualified for normal and accident conditions except for an amount demonstrated to be. acceptable based on a transport study.
The accident conditions will include MSLB as well as LOCA.
B.
. Containment Sump This submittal also describes the updated licensing basis for the containment recirculation sump.
The original basis assumed 50 percent screen blockage as recommended by RC 1.82.
The sump screens may now be postulated to be blocked by a combination of
-coatinns and insulation debris beyond 50 percent to a percentage which has been demonstrated acceptable by a mechanistic transport study.
In addition, the emernency core coolinn system (ECCS) transport path includinn the reactor core has now been explicitly-included in the licensing basis on the basis of its assessment for blockage in the transport study.
VI. CONCLUSION TVA identified three basic issues related to containment coatings at' SQN: programmatic, physical, and operability bases.
TVA has taken steps to address each of these issues with immediate corrective action and the establishment of a long-term program. The coatings maintenance program has been revised and strengthened. Coatings have been physically removed and repaired or have had barriers erected to prevent transport to the containment sump consistent with the operability basis. The operability basis has been reestablished with a conservative, physical transport study. The coatings maintenance program is in place and functioning.
The required physical repairs are completed. The transport study is complete, and its documentation is essentially complete. The licensing basis for the coatings and containment sump has been updated by this submittal.
In summary. TVA identified issues related to containment coatings, addressed each with corrective action as appropriate, instituted a long-term maintenance program, and established a sound operability basis. As a result of the efforts described in this submittal. TVA believes that all the SQN containment coatings issues have been resolved.,
TABLE I-1 SURFACE AREA 0F UNQUALIFIED CONTAINMENT COATINGS Unqualified Average Unqualified Average Location for LOCA DFT*
(mil)
(ft )
(mil)
(1) Upper Compartment 1,671 3
1,671 3
2.941(1) 7 2.941(1) 7 (2) Lower Compartment 1,379(2) 3 1,379(2) 3 702(1) 7 12,772 7
7,520 46 (3) RCP Motors 3,808 3
3,808 3
(4) Ice Condenser 863 3
863 3
(5) Accumulator 1,037 3
1,037 3
Rooms 3 & 4 NOTES:
1.
Top coat material is environmentally qualified, but subject to delamination (DFT outside specifications).
2.
Excluding RCP motors, but including allowance of 48 ft2 total for RCP appurtenance beyond screen platform.
3.
The numbers listed under the column for " location" correspond with the numbers designated on Figure I-1.
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d APPROXIMATE SURFACE AREA 0F NUCLEAR QUALIFIED COATINGS UPPER COMPARTMENT:
2 INORGANIC ZINC COATED STEEL 27,000 ft 2
EP0XY TOP-COATED STEEL 19,000 ft 2
EP0XY COATED CONCRETE 23,000 ft LOWER COMPARTMENT:
2 INORGANIC ZINC COATED STEEL 52,000 ft 2
EP0XY TOP-COATED STEEL 27,000 t 2
EP0XY COATED CONCRETE 25,000 ft 2
173,000 ft Figure I-1
l ENCLOSURE 2-EXECUTIVE
SUMMARY
EFFECTS OF SPECIFIC COATINGS AND INSUIATION DEBRIS ON THE OPERATION OF SEQUOYAH UNIT 2 FOR LOCA AND MSLB CONDITIONS T.W.
Ball' l
J.T. Dederer l-WESTINGHOUSE ELECTRIC CORPORATION PITTSBURGH, PENNSYLVANIA I
1
EXECUTIVE
SUMMARY
OF COATINGS ANALYSIS FOR SEQUOYAH 2 l
l
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Introduction:==
1 Westinghouse has been requested to perform an analysis of a specific quantity of unqualified coatings that have been identified within the containment of the Sequoyah Unit 2 plant. The concern is that should these coatings fail and detach following a loss of coolant accident (LOCA) or a main steam line break (MSLB) the potential may exist for transport of this
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debris to the emergency sump. In addition, the piping and RCS components are covered with refective metallic insulation (RMI), with the exception of the pressurizer safety valve loop seals which have a temporary covering of NUKON fiberglass insulation. High energy jets such as could be produced during a LOCA could damage this insulation and.cause it to detach from its surface. Following switchover of the RHR and containment spray pumps to the sump, it has been postulated that this debris could adversely affect the available net positive suction head (NpSHA) for these pumps.
The following summarizes the results of analyses performed to assess the transport potential of each of these types of coatings as well as the insulation materials previously mentioned.
Sump Radius of Influence:
The flowfield that is induced by the sump flow within the water pool has been calculated for different sump flowrates. This flowfield can then be used with the calculated particle settling velocities to predict debris trajectories for each debris type given the initial starting point for the debris. This methodology was used to calculate the trajectories that would just intercept the bottom of the sump, thus determining a radius of l
influence for each size of debris. Beyond this radius, debris entering the pool would not intercept the sump screens, but rather settle to the containment floor. This analysis also has shown that for the flow conditions expected to exist in the lower containment, no transport of coatings debris along the floor would be expected. The radius of influence was found to be 11.9 ft. for the average 3 mil debris, 10.4 ft. for the 7 mil debris, and 5.6 ft. for the 46 mil debris. These radii are referenced to the sump centurline. Within these radii, the following areas and types of coatings have been identified.
a.) 53.5 sq. ft. of vendor applied alkyd type coatings with an average dry film thickness (DFT) of 3 mils. These coatings are not qualified for LOCA or MSLB conditions.
b.) 326 sq. ft. of epoxy topcoatings with an average DFT of 46 mils applied to concrete surfaces in the lower containment. These coatings are qualified for LOCA but not MSLB conditions.
c.) 1013 sq. ft. of epoxy topcoatings with an average DFT of 7 mils applied to steel structures in the lower containment. These coatings are qualified for LOCA but not MSLB.
Ice Condenser Drain Effects:
l It was determined that three of the twenty ice condenser bays could possibly supply failed coatings to the lower containment within the radius of influence of the sump for particles with an average DFT of 3 mils. An on-site inspection was performed of the ice condenser unit to identify the cpecific coatings in question. It was determined that for these three bays 167 sq. ft. of coatings were unqualified in the upper plenum and 9 sq. ft.
were unqualified in the lower plenum for a total of 176 sq. ft. Subsequent to this, an analysis was performed to conservatively estimate the potential for this debris to reach the lower plenum of the ice condenser, end be carried through the 12 inch drain to the lower containment. The results of this analysis showed that only a very small amount of debris (less than 3 sq. ft.) might find its way out of the ice condenser unit effectively eliminating most of this debris from concern. This conclusion is valid for both LOCA and MSLB accidents.
Refueling Canal Drain Effects:
The refueling canal drains consist of two pipes of 13.5 inch inside diameter that exit flush with the refueling canal ceiling. The location of these drains is approximately 25 feet radially from the sump and 8 ft.
from the containment floor. Each of these drains has a 12 inch diameter circular disk mounted several inches below the drain outlet. The concern is that these drains, which return the upper compartment spray flow, may transport any debris from the upper compartment to the sump region. A three dimensional flowfield model was developed that calculated the flowfields in the water pool as a result of sump flow and refueling canal drain flow. The effect of the disks below the drains is to distribute the drain flow radially outwards from the drain centerline. Three dimensional debris particle trajectories were computed originating from the drain exit. In addition, the effect of a reduced water level (small LOCA) was evaluated to determine the impact on particle trajectories. The results of this analysis showed that any debris from these drains would settle to the containment floor before reaching the sump screens. This conclusion is valid for both MSLB and LOCA conditions.
NUKON Insulation Transport:
The pressurizer safety valve loop seals have been temporarily wrapped with NUKON fiberglass insulation. These loop seals are located at the top of the pressurizer and are fabricated from 6 inch piping. In the event of a small break failure of the piping in this area, jet forces could dislodge this insulation thus making it available for possible transport to the sump. A flowfield model was developed to estimate the flow velocities in the pressurizer area and assess the possibility of insulation debris transport. The results of this analysis show that there is insufficient flow velocity to transport sunken fragmented debris. Of the portion estimated to remain intact, but dislodged from the piping, only 9 sq. ft. is calculated to eventually reach the sump by floating on the water surface. The NUKON insulation is only a concern for a small LOCA in the pressurizer piping.
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1 Reflective Metallic Insulation:
i Reflective metallic insulation (RMI) is used almost exclusively throughout the containment to insulate piping and components. This insulation consists of a series of concentric stainless nteel foils l
encapsulated within a stainless steel jacket and end covers. The concern I
is that jet forces following a LOCA or MSLB could dislodge portions of I
this material and transport it to the sump area where it could contribute to screen blockage. 'To evaluate this concern, the methodology given in NUREG/CR-2791 was followed and examined several bounding breaks for their impact on RMI debris generation. The results of this evaluation indicate that at most, 45 per cent of the screen area could be blocked by RMI debris following a LOCA. RMI debris generation and transport has been l
determined not to be a problem in the event of a MSLB accident.
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NPSH Considerations:
l The NPSH calculations for the containment spray and RHR pumps have been extended to examine the effects of sump screen blockages of up to 90 per cent of the total area available. The results indicate that for both LOCA and MSLB conditions, adequate NPSH would remain even under these i
postulated severe blockage scenarios.
Sump Screen Blockage Effects:
1 Under LOCA conditions, only a total of 56.5 sq. ft. of coatings is at issue as well as possible blockage by RMI and NUKON insulation. The analyses performed on the insulation show that this material will preferentially block the lower portion of the screens only, leaving the upper portion of the screens available for coatings debris. The front ecreen is partly shadowed by the 45 inch diameter (including RMI) crossover leg pipe immediately in front of the sump. In addition, the top of the rear sump screen is shadowed by the presence of an 18 inch diameter (including insulation) RHR pipe that passes immediately above and slightly behind the rear of the sump. A pipe support for this line fabricated from 8 x 8 wide flange material is located to one side of the sump and acts to chield a portion of the rear screen and side screen. This shadowing is estimated to protect at least 12 per cent of the total sump screen area from blockage by coatings debris which is sufficient to maintain adequate NPSH for the pumps. For a MSLB, there would be no insulation debris reaching the sump, so that blockage could only occur from the portion of epoxy topcoatings and alkyd coatings that reached the screens. The same areas of the screening will be shadowed by the RHR and crossover leg piping and thus would remain open providing for continued operation of the sump. Flow from breaks in the crossover loop piping for loop 4 and the adjacent loops 1 and 3 have been evaluated and have been determined to not significantly affect the amount of screen blockage caused by either insulation or coatings debris.
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i Core Blockage Concerns:
The potential exists for coatings debris to pass through the sump gereens and be ingested into the RCS system where it would be recirculated through pumps, valves, heat exchangers and other RHR or containment spray equipment. For a LOCA this could occur ar, a result of the RHR pumps providing recirculation flow through the' core. For a MSLB, this could occur as a result of the charging pumps providing RCS makeup and RCP seal injection flow to the primary system. An evaluation was performed using a finite element fluid dynamics code to calculate the impact of different degrees of blockage on decaytheat removal in the core. The results of thisg study show that any blockage that could be formed by the debris at issue for both LOCA and MSLB conditions, would not significantly affect the decay heat removal capability. In addition, the mechanical components of the RCS and containment spray systems were evaluated and found to be negligibly impacted by the recirculating debris.
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Conclusions:==
The results of the comprehensive analyses just summarized indicate that the stated quantities and types of coatings and insulation would not block the emergency sump to the point where it is inoperable. Some degree of blockage, as discussed, would be expected but sufficient screen area would remain open to allow for safe operation of both the containment spray and RHR pumps. Furthermore, should this debris be ingested into the RCS, there would be no significant impact on long term coolability.
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ENCLOSURE 3 COMMITMENT Appropriate revision to the SQN FSAR will be made in the'next regular update scheduled for April 1988 to reflect the updated licensing basis for SQN containment coatings and the containment sump.
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