IR 05000324/1988013

Insp Repts 50-324/88-13 & 50-325/88-13 on 880307-11.No Violations or Deviations Noted.Major Areas Inspected: Previous Open Items & Mark I Containment long-term Program Mod

ML20151W200
Person / Time
Site:	Brunswick
Issue date:	04/22/1988
From:	Blake J, Robert Carrion, Chou R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20151W192	List: IR 05000324/1988013 ML20151W187
References
50-324-88-13, 50-325-88-13, NUDOCS 8805030325
Download: ML20151W200 (12)

Text

,

n dip UNITED STATES

.

'.

'/'e p'

q 7,7 ,

NUCLEAR REGULATORY COMMISSION Region ii

< / j 101 MARIETTA STREET. * ';

's ATL ANTA, G EORGI A 30323 gj.....,/

Report Nos.: 50-325/88-13 and 50-324/88-13 Licensee: Carolina Power and Light Company l P. O. Box 1551 Raleigh, NC 27602

'

Docket Nos.: 50-325 and 50-324 License Nos.: OPR-71 and DPR-62 Facility Name: Brunswick 1 and 2 Inspection Conducted: March 7-11 1988 Inspectors: k ton C/bN R. C Date Signed i & S . atrion Date Signed Approved by: tL/96 . J PdRe, Chief Date Signed M erdals and Processes Section 0 vision of Reactor Safety SUMMARY scope: This routine, announced inspection was in the areas of the previous open items and Mark I Containment Long Term Program Modificatio Results: No violations or deviations were identified, s8050j$$$k$$0 D$^

PDR O

n ,

. .

.

-

.,

l

!

REPORT DETAILS 1.~ Persons Contacted Licensee Employees J. Cooper, Senior Specialist

• R. Dietz, Plant General Manager T. Eason, QC Insnector

• E. R. Eckstein, Technical Support Manager

• K. E..Enzor, Regulatory Compliance Director R. Fronerath, Senior Engineer

• W. M. Hogle, System Engineering Supervisor

• P. W. Howe, Vice President - BNP W. Monroe, Civil Principal Engineer M. Pastra Compliance Specialist

• R.M.Poulk,ProjectSpecialistforNRC D. Simkins, Seninor Structural Engineer

• J. A. Smith, Administrative Support Director

• Tripp, Senior Engineer - Construction P. Wenzel, Project Engineer

• A. M. Worth, Engineering Supervisor Other licensee employees contacted included construction craftsmen, engineers, technicians, mechanics, and office personne Other Organization H. Painter, Structural Engineer, United Engineers and Construction In (UE&C)

NRC Resident Inspector

• Ruland, Senior Resident Inspector

• Attended exit interview Exit Interview The inspection scope and findings were summarized on March 11, 1988, with those persons indicated in paragraph 1 above. The inspectors described the areas inspected and discussed in detail the inspection finding No dissenting comments were received from the license The following new item was identified during this inspection:

(0 pen) Unresolved Item (UNR) 50-324/88-13-01, As-built Drawing Discrepancies for Torus External Piping System ,

-- .

]

.

,

.

The licensee did not identify as proprietary any of the material provided to or reviewed by the inspectors during this inspectio . Licensee Action on Previous Enforcement Matters (Closed) UNR 50-325, 324/83-01-01, Plant Unique Analysis Report -

Column Loads Verification. This matter concerned the facts that an inconsistent load magnitude, inconsistent load units and an unbraced leagth were used in Plant Unique Analysis Report (PUAR) or design calculation. Sixty-nine kips were used for the column design described in Section 1.12 of PUAR which was inconsistent with the load shown in Figure 1.12-1 of PUAR where 90 kips were shown on the same colum The load units (ksi) shown in Table 3.7.4-1, qualification of columns for pools swell and thrust loads and load units (kips) used in the column calculations are inconsistent. The unbraced length of 5.8 ft. used in the column design calculation is not conservativ The inspectors held discussions with the licensee's responsible engineers and reviewed the information provide The PUAR has been revised to show the actual 69 kips load in Figure 1.12-1 instead of the 90 kips load previously shown and to show the correct units of kips in Table 3.7.4-1 to be consistent with units used in design calculation. The licensee stated that the problem of 90 kips shown in Figure 1.12-1 was an engineer's oversight, in not revising the preliminary load to be consistence with the latest load of 69 kips; the load unit inconsistency appeared to be a typographical erro For nonconservatism of the unbraced length used in column design calculations, the licensee stated the reduced column capacity based on the conservative calculation would be 5% which was much less than the allowable margin of 50%. Based on the licensee corrective actions and explanation, UNR 50-325, 324/83-01-01 is considered close (Closed) UNR 50-325, 324/83-01-03, Plant Unique Analysis Report -

Vacuum Breaker Verification. This matter concerned the fact that neither GE nor the licensee performed a technical review with regards to the evaluation of the Mark I vacuum breaker. The evaluation for vacuum breaker based on the input data provided by the licensee was performed by Continum Dynamics, Inc. (CDI) on Purchase Order No. 205-XJ102 for the General Electrical Company, dated August 198 The inspectors held discussions with the licensee responsible engineer and reviewed the information provide The licensee stated that most of the data was provided from field and all the records were kept in the plant. Therefore, the licensee responsible engineer reviewed the input data against the existing drawings or records and concluded that the evaluation of the vacuum breaker performed by CDI was acceptable. The ifcensee did not prepare an official review report for the evaluation of the vacuum breaker, instead, the responsible engineer stated his review approach, (QA instruction for processing vendor document submittals, comparison of the valve

_ _ _ _ _ _

. .

,

.

and torus physical data, input data check, output impacts and velocities review etc.) in a site memorandum, File No. B80-071, BESU 20S79 attached to the response fil Based on the licensee action taken as stated above, UNR 50-325, 324/83-01-03 is considered close c. (0 pen) UNR 50-325, 324/87-18-01, Corrective Action On Violation 50-324/85-19-0 This UNR requested that the licensee perform review and correction of fillet welds smaller than code allowabl The previous inspectors identified several cases where fillet welds shown on drawings do not satisfy the requirements of the Code of Recor The report by Reedy Associates commissioned by the licensee presents a philosophical change in thinking by the AISC, AWS, and ASME since the adoption of the Codes of Record concerning fillet weld size requirement The later requirements are based upon strength requirements rather than the quench effects on small welds, which could lead to shrinkage crackin These ideas will be carefully weighed in the continued investigation of this UN This item remains ope d. (0 pen) UNR 50-325, 324/87-18-02, Approval of Overlap Modeling Technique This matter concerned the fact that the Overlap Modeling Technique in the UE&C Procedure DEDP-2607, Revision 1, was used for computerized piping analysis in Brunswick Stress Analysis Problems while the procedure did not meet the overlap modeling criteria recommended by NUREG/CR-1980 BNL-NUREG-5135 The inspectors held di mussions with the licensee responsible engineers and reviewed the information provided. The Study Report No. 7992.001-S-M-037, Rev. 2, Evaluation of Overlap Zones, and Calculation Set No. 9527-9-PSSS-24-F, Rev. O performed by UE&C for Brunswick plant were reviewad. The UE&C approach was to identify the models that utilized main run overlap and branch line overlap, establish how far the models were overlapped and identify / justify the approach utilized to evaluate the capacity of supports within the overlap regio There were 18 overlap piping models (main run and branch lines) identified after the careful review, with the breakdown as one 4" RHR Head Spray Line,15 small bore instrument air lines, and two branch lines. Two branch models (lines) were considered acceptable by the UE&C based on the original analyses which met the branch overlap requirement (Reference 7865.007-5-M-020) and the

, supports were designed to the highest load from either model of overla The 15 small bore main run models (instrument air) were reviewed by applying, to representative samples, a more conservative approach to calculate loads on supports in the overlap zone Calculation Set No. 9527-9-PSSS-24-F was reviewed by inspector This calculation selected four overlap models of Iso 176 to Iso. 1778, Iso. 1778 to Iso. 177A, Iso. 179 to Iso. 180, and Iso. 180 to Iso.181 and demonstrated the support design in overlap regic' to

. .

,

.

be acceptable by using the absolute sum of loads from two models with overlap since the design loads from the absolute sum were still well below the capacity of support provided. The UE&C concluded the overlap models for two branches and 15 small bore instrument lines to be adequate and acceptable even if the overlap modeling methods did not meet NUREG design criteri The inspectors considered the UE&C conclusion on the above to be acceptabl The licensee did reanalysis on the 4" RHR main run as Calculation ID No.1E11-554-01, Rev. Pl. This reanalysis combined Isos 554, 555, and 556 as one computer run to eliminate overlap. An as-built walkdown was performed by the licensee on Isos. 554, 555, and 556 to verify all support locations and piping dimensions. The walkdown showed that two supports were incorrectly modeled and two small bore lines were not modeled. Therefore, a direct comparison is not possible. Per the reanalysis, the plaing systems was qualified for short term and modification was requi red to Support No.1E11-899G495, -PG498, 1 MUD-207PG45,1MD-207A46, and PS-4070 for long term qualificatio The licensee's responsible engineer indicated the support modifications would be finished during the coming outage around September 198 Pending the completion of the above support modifications and documentations, UNR 50-325, 324/87-18-02 remains ope . Unresolved Items Unresolved items are matters about which more information is required to determine whether they are acceptable or may involve violations or deviations. One unresolved item identified during this inspection is discussed in Paragraph . Mark I Containment Long Term Modification for Units 1 and 2 (Module No. 25585)

(0 pen) TI 2515/85, Unresolved Safety Issue A-7. This is the fourth l inspection on Mark I Containment Long Term Program (LTP) Modification.

'

The previous inspectors did inspections at construction stage on welding i

and structures for torus modification. The Inspection Report No. 50-325, l 324/80-07 inspected the structural modification for Unit 2 and the I document preparations for Unit 1. The Inspection Report No. 50-325/83-07 inspected welding (Unit 1). Inspection Report No. 50-325, 324/83-01 documanted the review of PUAR for structural modifications such as downcomer and tie, new column for vent header, platform, RHR test line supports, suppression pool strainer, vacuum breaker, electric penetration box etc. , and the field walkdown to verify the additional new pipe support Background The Brunswick Units 1 and 2 Containment Systems are one of the first generation General Electric (CE) Boiling Water Reactor (BWR) nuclear steam supply systems housed in a containment structure designated as

.

~

.

the Mark I Containment Systems. The original design of the Mark I Containment System included pressure and temperature loads associated with a Loss-of-Coolant Accident (LOCA), seismic loads, dead loads, jet-impingement loads, hydrostatic loads due to water in the suppression chamber, overload pressure test loads, and construction loads. Due to additional, hydrodynamic loads, which were discovered later resulting from the dynamic ef fects of drywell air and steam being rapidly forced into the suppression pool (torus) during a postulated LOCA and from suppression pool response to Safety Relief Valve (SRV) operation generally associated with plant transient operating conditions, the NRC required licensees to have a detailed reevaluation of the Mark I Containment System. The resolution of this issue was divided into a short-term program and a long-term progra The Short-term Program (STP) provided a raaid assessment of the adequacy of the containment to maintain its integrity and functional capability when subjected to the loads induced by a design-basis LOCA, and used NUREG-0408 as a guideline. The NRC had approved the Brunswick's STP. The long-term program was to maintain a margin of safety when the Mark I containment structures and piping systems are subjected to additional hydrodynamic loads and was identified by NRC as Unresolved Safety Issue (USI) A-7, Mark I Long Term Program which would use NUREG-0661 as design criteria. The licensee, based on detailed testing, analytical work and modifications completed by 1982, summarized and submitted the result to NRC as a Plant Unique Analysis Report (PUAR) dated November 11, 198 The NRC reviewed the licensee's PUAR for the pool dynamic and structural load aspects against the design criteria, NUREG-0661 and approved the PUAR on March 19, 198 This inspection and the subsequent inspections to come later are to verify that the licensee had modified the plant with appropriate procedures, design, analysis, calculations and in accordance with the licensee commitments stated in the PUAR. The inspectors held discussions with the licensee's responsible engineers and engineer from Architecture / Engineer firm, UE&C. The walkdown reinspection areas included torus structure modifications on vent header columns, deflectors, platforms, pipe supports, temperature monitoring system, and attached external piping systems. The structural modifications inside the torus and below the torus water line such as downcomer tie and safety relief valve quenchers (T-Quencher) were also discusse Unit 2 was in a refueling outage, therefore all the walkdown reinspection was performed in Unit 2. To verify the licensee commitment and performance, the inspectors randomly selected the following restraints and structural components that had been QC final inspected to see if they complied with commitments and as-built drawing The restraints and structures were reinspected with the assistance of the licensee's QC inspector, engineers, and craftsme .. . . . - _ _ _ . -. .-

. .

,

.

r b. Torus Attached External Piping Systems Eighteen pipe supports in three isometrics were selected for reinspection. Two discrepancies were found. The three isometrics are Steam Relief Valve Discharge Drawing No. 2820722214, Rev. B for Item No.1 to 7; Z820722219, Rev. A for Item No. 8 to 12; and Z820722224, Rev. A for Item No. 13 to 1 TABLE 1 Item N Support N Rev. N Walkdown Comments 1- 2821-33VH247 2 None 2 2821-33SS249 3 None

'

3 2821-3355250 3 None

4 2821-33SS251 4 None

5 2821-33VH252 2 None -

,

6 2821-335S332 4 None  !

.

'

7 2821-33PG349 0 None 8 2821-20SS250 i 4 None

'

.

9 2821-20VH255 2 Spring can end ,

attachment connected to composite i beam was different from the ,

'

drawing i shown as r connected !

to wide flange beam

, 6 WF-1 l

'

10 2821-205S257 3 None 11 2821-20VH259 2 None

12 2821-20SS261 3 None i 1 13 2821-58PG275 6 None

! 14 2821-5855277 5 None i 15 2B21-58VH278 3 None l 16 2821-5855281 4 None

17 2821-58VH282 2 Fillet weld

,

on two sides .

'

i of base i- plate for i

! connecting

to other l restraint 7 j was

'

l different :

! from the !

'

<

f

-.

, .

,

' -

.

drawing shown for weld aroun None The above restraints were in high radiation drywell area. The restraints were partially reinspected against their detail drawings for configuration, identification, fastener / anchor installation, member size, weldt, dimensions, gap, clearance, rust, maintenance, and damage /protectfo c. Torus Modification - Internal The Brunswick suppression chamber consists of a reinforced concrete, steel lined toru This structure sacisfies the LTP criteria without modification. Therefore, the inspectors walked down the torus inside

,

to reinspect the structural modifications such as vent h;ader support -

column, ring plate, platform and walkway, deflector and support, Residual Heat Removal (RHR) Test Line, RHR Containment Cooling Line, Monorail, temperature monitoring system, vent header and downcomer

-

intersection reinforcement, and Vacuum Breake '

(1) Vent Header Support Column and Ring Plate i At approximately 0.6 second after pool swell initiation, an upward pressure on the downcomers, and vent header in the torus '

tends to move the vent header upward. To prevent the upward  ;

displacement, the vent header is connected to the suppression chamber inner surface at the top of the vent header sup) ort column Total of 684 kips at each vent and vent heacer ,

intersection due to dynamic load is transferred to top inner "

surface of torus through eight support columns (four existing and four new) as shown in Figures 1.12-1 and 1.12-2 of PUA A l 12" by 8" plate is used for each new column to transfer the load  !

to the torus. Each of the new columns transfer an average of 69 i kips to the torus and each of the existinp columns transfers 102 kips. A ring plate around vent header is providea a distribute

'

, the concentrated load from the support column to the vent header  :

shell plate. Drawing No. F-01352, Suppression Cha.aber Ring Vent l Header Supports, Rev. 7 was used to check the new support columns and ring plates for vent teaders at azimuths 135 , 225', >

270 , and 315'. The 6" 4 sch 80 support column, ring plate 1"x6", 3% pipe4"4 4 pin, andsch.40 8" $ XXS pipepipe for for bracing,1" eye plates, and other details were checked against the detail drawing for as-built condition. The 6" $ sch.80 pipes, ring slate 1"x6", and their locations were confirmed to page 3-55, F:gures 1.12-1, 1.12-2, and Table 2.3.2-2 of PUAR.

,

,

>-~m"---gu-c

, m

. .

,

'

.-  ;

8 l (2) Platform and Walkway i

Platform support columns were made up of two back-to-back angles  ;

before modificatio Structural evaluations revealed that the existing columns could not resist the uplift load acting on the platforms and walkways during the pool swell events. The walkways had been relocated to the top of the vent header around the torus to be shielded by the vent header from pool swell load The platforms had been completely redesigned to resist pool swell and other loads and rebuil The modifications included new 6" $ pipe columns which were added above the platforms to resist pool swell load Drawing Nos. F-1353, .

Suppression Chamber New (Mark I) Platform Framing Plans and "

'

Details, Rev. 4 and F-1357, Suppression Chamber Relocated Existed Walkways Plans and Details, Rev. 2 were used to check -

platform details at Azimuths 135 , 225*, 270", and 315 . The beam TS8x6 and TS6x4, Celumn 6" $ pipe and Sd & pipe, grating and connections were checked for confirmation with drawing The' 6" Q pipes used for platform colan and walkways around the top of torus were confirmed to Page 2-18 cf PUA (3) Deflector and Support The deflector was installed directly beneath the ring header and on the surface of the water to direct pool swell flow away from the ring header and reduce the impact pressure on the ring heade The typical deflector is a 20-inch $ pipe with two angles welded at the sides. It is supported at the ring header and runs continuously from one vent bay to the adjacent vent bay, and ends with cantilevers at two ends before it meets the SRV discharge lines. The deflector sits on a one inch support plate which is accompanied by four 3/4 inch check plates and four 3/4 inch stiffener plate Pawing Nos. F-01322, Suppression Chamber Ring Vent Header Deflector, South Half,

,

Rev. 6 and F-01324, Suppression Chamber Ring Vent Header Deflector Sections and Details were used to check the installed

'

i '

configurations for deflectors, deflector supports and details [

per visual inspection due to the deflectors and supp' orts being away from platform. The deflectors consisted of 20 4 sch.120 p,i,pe and L8x8 (angle) and the deflector support plate thickness  ;

I shown on the drawings were checked to confirm Fi

'

sketches for Ringer Header Deflector (Pages 1 to 4) gures 3.2-6, of PUA (4) RHR Test Line The RHR Test Line was analyzed based on the existing supports and was showed that the piping and supports were highly overstressed due to froth impingement forces alone. After adding additional four supports, the line was found acceptable for the froth impingement forces. Drawing Nos. F-02813,

, Suppression Pool Piping and Arrangement, Rev. 19 and r l

l

,

..~,..._,,__m, - _ - . - _ , _ . _ - . , _ - _ _ -- - -

-y. , _. _ ,

. _ _ . _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _

. .

,

.. -

.

9 <

-9527-F-2429, Suppression Chamber RHR Test Line Pipe Support Details, Rev. 0 were used to check Support Nos. PS-8, PS-9, PS-14 and PS-18. The dimensions, member sizes, clearances, welds, base plates and miscellaneous plates for the supports were checked to the above detail drawings. One discrepancy was found. The base plate size 3/4"x8"x1'-6" found in field for Support No. PS-9 was not shown in the detail drawing. The licensee's responsible engineer quickly secrched for the as-built document and found that the base plate size was correct but missing in the drawing due to the drafting erro They presented the as-built document and the new revised drawing-to show base plate size to the inspectors before the exit meetin !

The RHR Test Line was shown and confirmed on Page 2-19 and  !

Figure 2.3.2-2 of PUA '

'

(5) RHR Containment Cooling Line This line is also known as the torus spray heaaer. This line penetrates the torus three feet above water rising along the inner surface of the torus to the zenith and is continuous along the circumference of toru The line between penetration and zenith t of torus had no supports originally. Analysis of the existing line showed that it was not acceptable due to 3001 swell loads, i The line was found acceptable with the four adcitional sup) ort Drawing No. 9527-F-2431, Suppression Chamber Pipe Support Jetail -

Sheet 2, Rev. 0 was used to check support Support No. 22A and 22F were partially physically checked since they were near the walkway Support Nos. PS-19A, PS-19F, PS-20A, PS-20F, PS-21A, and PS-21F were visually inspected against the detail drawing since they were far away from walkways. The RHR Containment Cooling Line was stated oa Page 2 18 of PUAR. The Model of this line was shown on Figure 2.3.2-1 of PUA (6) Monorail The monorail must be shown that its element failure does not result in significant damage to safety-related items. Based on the generic froth impingement forces, the monorail was not acceptabl The monorail was made of 12 I @ 31.8 LB and was supported every 7 ft.10-1/3 in, along the circumference of the containmen Twenty-four 1/4"$ stainless steel wire rope ,

supports were added. These supports are inactive during operation of the monorail and were designed to support the monorail if monorail supports fail due to the froth impingement forces during LOC Drawing No. 9527-F-1779, Suppression Chamber Monorail Supports, Rev. 0, was used for visual inspection on Support No. M;-10,11,12 and 13 due to the supports away from walkway Monorail modification was stated in Page 2-19 of PUA _

, .

-

. . .

.

(7) Suppression Pool Temperature Monitoring System The suppression pool temperature monitoring system is required

.per NUREG-0661 to ensure that the suppression pool is within the allowable limits set forth in the plant Technical Specifications. The numbers and distribution of the pool temperature sensors are required to collect the sufficient information and provide the means for a reasonable measure of the bulk temperature. The installed temperature monitoring systas for air and water at pool around the vent header and platform was noticed by the inspectors. An unscheduled visual inspection without the drawings or documents was performed by the inspectors during the platform modification walkdown. There were two electric posts for air at vent header and two electric posts for water submerging into water along the platform column The licensee's responsible construction engineer could not remember the system having been installed before Mark I Containment LTP modification or modified during Mark I modification This system was not addressed in the Brunswick's PUAR to demonstrate the system met the NUREG-0661 requirement The UE&C and licensee's responsible engineers are searching for information and document for this system. This item will be reviewed later for system connecting to control room for monitoring and the evaluation for satisfaction when the drawings and documents are availabl (8) Vent Header and Downcomer Intersection Reinforcement The vent header and downcomer intersection is the area where maximum stresses occur due to condensation oscillation, chugging and safety relief valve loads. This intersection is identified as the most critical location in the vent system for fatigue evaluation. For the purpose of a conservative fatigue evaluation, an estimated 2000 equivalent maximum stress cycles

'

have been used. The maximum cumulative usage for fatigue for vent header and downcomer intersection is 0.44 per Table 3.8.5.4-1 of PUA To achieve the above cumulative usage

'

for fatigue, three 1/2" thick plates are required to be added for reinforcemen Drawing No. F-01335, Suppression Chamber

>

Modification to Downcomer, Rev. 2 was used to check 1/2" reinforcement plates. The above drawing was reviewed for commitment stated in Page 3-55 and Figure 3.6.1.1-2 of PUA (9) Vacuum Breaker

,

'

The vacuum breaker was bolted to the flange pipe which had a diameter of either 18-in, or 21-i The flange was welded to the vent header. Per the licensee's responsible engineer the vacuum breaker was modified to improve the valve function during the Mark I LTP modification. The vacuum breaker was visually

'

inspected for configuration without the drawing.

.

s

_

-. _ - _ _______ _

..

e t 11 Calculation Review In conjunction with the Mark I modifications, the following calculations were reviewed for methodology, completeness, accuracy, and assumptions:

9527-1-SC-TE-11-F, Rev. 2 RHR Test Line Supports Inside Torus 9527-1-SC-PL-05, Rev. 1 Platforms and Walkways Inside Torus 9527-E-SC-55-9, Rev. O Downcomer Tie Analysis 9527-E-SC-SR-3-F, Rev. 1 Analysis of Safety / Relief Valve Discharge Line and T-QuencherSupports Preliminary determinations are that these calculations are acceptabl However, a more detailed investigation is necessary to make a final determinatio Findings and Summary BaseJ on the above findings, the inspectors summarized the results and identified the new open items as follows:

-

(0 pen) UNR 50-324/88-13-01, As-built Drawing Discrepancies for Torus External Piping Systems'. Two discrepancies were found in pipe supports as stated at Table 1, Paragraph 5(b).

No violations or deviations were identified in this area.

' . _ . - _ - - . _ _- - _ _ . _ _ _ , .

-_. __ . _ . . _ _