IR 05000324/1989018
| ML20246D190 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 08/10/1989 |
| From: | Belisle G, Lenahan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20246D169 | List: |
| References | |
| 50-324-89-18, 50-325-89-18, IEB-79-14, NUDOCS 8908250284 | |
| Download: ML20246D190 (6) | |
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NUCLEAR REGULATORY COMMISslON
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- Report Nos.: 50-325/89-18 and 50-324/89-18
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Licensee:. Carolina Power and Light Company
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P. O., Box 1551 Raleigh, NC 27602 Docket Nos.: 50-325 and 50-324 License Nos.: DPR-71 and DPR-62
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Facility Name:
Brunswick 1 and 2
. Inspection Conducted: July 10-14. 1989 Inspector:
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Date' Signed J. J. LenahaD'
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G. A. (Belisle; Chief /
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i Test Programs.Section
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Engineering Branch
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Division of_ Reactor Safety:
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SUMMARY
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Scope:
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This routine, unannounced inspection,was conducted in.the areas b the snubber c
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i surveillance program, licensee identified ' items, and licensee action on previous inspection findings.
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' Results:
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One violation was identified pertaining to failure of the licensee to conduct.
an; adequate review of the Standby Gas Treatment (SBGT) system supports, i aragraph 4.b.
p An unresolved item was also identified regarding possible deficiencies in the-design of supplemental structural steel supporting safety-related equipment, i;
paragraph 4.b.
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The violation and unresolved item indicate weaknesses in the licensee's
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corrective action and design control programs.
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Procedure PT-19.6.4, Revision 3, Safety-Related Snubber ' Seal Life Monitoring b.
Review of Snubber Surveillance Records The inspector examined the results of visual inspections performed on Unit I snubbers in November 1988 and in. February 1989 - March,1989.
The. inspector also reviewed the results of functional tests performed on Unit I snubbers. in November 1988 and the status of the Unit i
snubber seal life monitoring program through March 1989.
Within the area inspected, no violations or deviations were identified.
3.
Licensee Identified Items a.
(Closed)LER 325/87-005: Primary Containment Isolation Valve Problem Revealed Through Local Leak Rate Testing.
During the 1987 Unit i refueling outage, local leak rate testing (LLRT) of primary containment isolation valves identified nonqualifiable leakage rates on four valves, feedwater valves B21-F010A and F032A, and containment atmosphere control (CAC) system valves CAC-SV-1211E and 3439.
The-c feedwater valves were located on the same line, F010A is the inboard
isolation check valve, and F-032A is the motor-operated outboard isolation valve.. The licensee made a four hour red phone report to NRC on February 28, 1987, to report the LLRT failure on this system.
The cause of the LLRT failure for valve F-032A was a cracked weld on the valve body packing leak off line. The cause of the cracked weld was indeterminate, but most likely was due to application of an external force on the leak off line.
The valve packing as-replaced with
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another type and the subject' leak off line was cut and capped. The cause of the LLRT failure for valve F010A was deterioration of the ethyl propolyne (EP't) soft seat material.
This valve was repaired by replacing the soft seat material with a different type EPR seat
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furnished by another manufacturer.
Discussions with licensee engineers disclosed that the new seat was fabricated from an EPR which was subjected to a different curing process. This resulted in a stevice life of five years versus the eighteen months service life for the soft seat material used previously.
The CAC valves failed the LLRT test as a result of flat spots on the soft seats of valve discs.
The discs were replaced.
All four valves were repaired and retested.
The LLRT retest results demonstrated the valves were acceptable. The inspector examined the results of the LLRT performed on the repaired
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L valves and verified that the tests met acceptance criteria.
The inspector examined the LLRT data for the subsequent testing performed during the 1988 refueling outage on the above mentioned four valves.
Valve B21-F010A failed the LLRT again, while the LLRT results were acceptable for the other three valves.
The 1988 LLRT failure for valve B21-F010A occurred due to degradation of the EPR valve soft seat (seal ring) material.
This test failure, along with others on-several additional valves, was reported to NRC in LER 325/89-025.
Valve number B21-F010B also failed to meet the LLRT acceptance l
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criteria.
However, the ' outboard isolation valves, - B21-F032A and F032B, met l the LLRT acceptance criteria.
Review of LLRT data.for
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.. tests conducted since.1980; showed that both of' these. inboard
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' isolation check valves, and the same two valves installed in Unit 2
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The licensee has' not :yet' determined the. root cause of' the repetitive -
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failure of the EPR seal ring on valves B21-F010A and B21-F010B.. ~ The:
licensee has performed several modifications to those valves and, to-date,/ have not been ' able to correct the problem.. The licensee'is'
presently. considering ' replacing : these valves. NRC.will perform further. review of_. the ? licensee's efforts to resolve the local
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'leakrate testing problems being experienced with the Units. I and 21 isolation valves 'during followup on LER 325/88-025..
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(Closed) ~ LER 325/88-035:
-SBGT Trains Common Discharge Line Determined to be not Seismically Qualified on Both Unit l'and Unit 2 Rendering: SBGT-Trains and' Secondary Containment ' Inoperable.
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December 22, 1988, the licensee determined that the Unit 1 Standby
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Gas Treatment (SBGT) line was not seismically qualified due to pipe
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support design deficiencies.
The supports were modified and;the system. returned to operable status on December 24, 1988.
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of'this3 problem and the licensee' corrective actions are discussed in paragraph -4.b' below, under resolution' of - Unresolved Item (URI) 325,324/88-41-02.
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Action on. Previous Inspection Findings (92701, 92702)
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- (0 pen) Inspector Followup Item.324,325/88-11-01, Vent Path Model.
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The. license'e has developed a. vent path model to determine the worst
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case flows _ and pressures through containment vent lines during venting 'of the drywell and suppression chamber after a hypothetical
' severe accident..The venting flows were studied for various cases.
'The results of the; analysis indicated th6t the vent system is capable of removing a constant. decay heat from the containment. 'However,-the results of the analysis indicated that the allowable ' stresses would F
be-exceeded in the ~ ductwork adjacent.to the purge fans.
The licensee's Nuclear Engineering Department is presently performing additional analysis on the ductwork to determine if modifications will be necessary to the system, or if the pressures within the ductwork could be sufficiently reduced by restricting the vent valve openings to 30, provided that the valves with these restricted openings could adequately vent the containment.
The inspector also questioned-licensee engineers regarding the effect of the higher pressures on
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the vent line piping supports and whether the new accident design pressures would control design of the pipe supports.
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evaluations will be completed by December 15, 1989.
Pending review of the completed analyses, IFI 324,325/88-11-01 will remain open.
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(Closed) Unresolved. Item 325,324/88-41-02, SBGT System Pipe Supports Not Short Term Qualified.
On December 22, 1988, the licensee
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determined that a Unit'1 SBGT line was not seismically qualified
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.Two supports,. numbers ISGT-GVH30 and ISGT-GVH31. were modified on the line and the system was restored to
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24, 1988.
The support modifications are-operable status on December shown on CPM. design sketch ' numbers SK-S-88-017-30,. Sheet 1 of 1; SK-S-88-017-31, Sheets 1 and 2 of 2; and SK-S-88-018-24, Sheets 1 and 2 of 2.
.The inspecter examined the supports and verified that they.
had been modified per the requirements shown on the sketches.
On December 27, 1988, the licensee' determined that a~ similar problem had existed on the corresponding Unit 2 SBGT line priorto-
' November 17,.1988, when a non-Q radwaste pipe support was removed from the structural steel beam which also supported.the SBGT line.
The'non-Q radwaste line was attached to a new pipe support supported from a reinforced concrete wall in ' the' Unit 2 reactor building.
Details of the new support are shown on sketch number SK-S-88-018-22.
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The inspector examined the new support and verified that this non-Q radwaste' line was ~ no longer supported from the same beam which
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supported the.SBGT line.
The Unit 2 support problem was first found in October 1985.. Du ri ng ".t walkdown of the system, support 2-SGT-6VH30, a variable spring can c was found with the cold setting pin still installed.
This hanger supports the drywell purge fans' discharge line which is connected to the. SBGT system common discharge line to the stack.
Thus, the support is included in the stress analysis of the SBGT system. Work request 2-M-85-4074 was written on October 16, 1985, to remove-the pin and reset. the spring can.
The pin was removed on November'7,
'1985, and the structural steel beam was bent. Engineering Evaluation Report (EER) 85-0364 was written and approved on November 14. 1985, justifying' interim operability of the SBGT system with the support inoperable.
The licensee's EER permitted continued operation with the bent steel member until the Unit 2. refueling outage.
Calcula-tions done in support of the EER showed that the adjacent-supports could handle the redistributed load assuming that the damaged support was. removed.
The refueling' outage started on November 30, 1985, and ended' June 15,.1986. The support was not modified during the' outage as directed in the EER, and the required modification and EER was apparently overlooked and forgotten.
In October 1988, during a walkdown being conducted to complete the piping analysis required by IE Bulletin 79-14, support number 2-SGT-6VH30 was re-identified as a questionable support. During the 1988 re-evaluation of this support, it was discovered that the same support had been previously addressed in 1985 under EER 85-0364.
However, reexamination of the EER disclosed that the integrity of the structural steel-beam which supported the spring hanger had not been evaluated considering the actual loads acting on this beam.
The calculations performed. in 1988 disclosed that the beam would fail under seismic loads due to the fact that two additional supports number 2SGT6P31, end the non-Q radwaste line, were attached to this
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The licensee then evaluated the corresponding Unit 1 SBGT
. support and discovered the same problem. That the licensee's failure to perform an adequate evaluation of the SBGT supports, the failure to modify Unit 2 support 2SGT-6VH30 within the time. frame directed by-EER 85-0364, and the failure to perform an evaluation of the corresponding Unit I support ISGT-6VH30 in 1985 when the problem was i
initially discovered was identified to the licensee as Violation 325,324/89-18-01, Inadequate Engineering Evaluation of Pipe Support for Short Term Operation.
Review of Revision 2 of LER 88-035, dated June 6, 1989, and discussions with licensee engineers disclosed that design calculations no longer existed for the supplementary steel beams which support safety-related pipe supports, electrical raceways, HVAC duct systems, instrumentation, and various other equipment.
During a walkdown of the Units I and 2 reactor. buildings the inspector identified several areas where the supplementary steel beams appeared'
to support large loads. The inspector expressed concern regarding the lack of these calculations and the failure of the licensee to resolve the questions. regarding design of supplemental steel identified in LER 325/88-035.
Pending further review by NRC, this problem was identified as Unresolved Item 325,324/89-02, Apparent Deficiencies in Design of Supplemental Structural Steel.
Within the area. inspected, no deviation's were identified.
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Exit Interview The inspection scope and results were summarized on July 14, 1989, with those persons indicated.in paragraph 1.
The inspector described the areas inspected and discussed in detail the inspection results listed above.
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Proprietary < information is not contained in this report.
Dissentiag comments were not received from the licensee.
Violation 325,324/89-18-01, Inadequate Engineering Evaluation of Pipe
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Support for Short Term Operation, paragraph 4.b.
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Unresolved Item 325,324/89-18-02, Apparent Deficiencies in Design of Supple:nental Structural Steel, paragraph 4.b.
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