ML20138E508
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/NEA Mehe NoeionelEnoueeen%g Laboratory December 6, 1994 i
Mr. Thomas X. McLellan, Project Officer 1
c/o Document Control Desk Materials and Chemical Engineering Branch Division of Engineering U.S. Nuclear Regulatory Commission Washington, DC 20555 TRANSMITTAL OF THE TECHNICAL EVALUATION LETTER REPORT ON THE SECOND 10-YEAR INTERVAL ISI REQUEST FOR RELIEF NO. 18 FOR ST. LUCIE NUCLEAR POWER PLANT, j
UNIT 2 - BWB-52-94
Reference:
NRC Form 189, " Technical Assistance in Support of the NRC Inservice Inspection Program" (FIN-L2556, Task Order 30c, NRC TAC No. M88087)
Dear Mr. McLellan:
This report completes the INEL review of the subject request for relief for the second 10-year ISI interval at St. Lucie Nuclear Power Plant, Unit 2.
This request for relief was submitted by Florida Power and Light, in a letter dated October 15, 1993.
This report completes the INEL work under Task Order 30c of NRC FIN-L2556 for NRC TAC No. M88087.
Sincerely, OQ B. W. Brown, Principal Investigator NDE Engineering Analysis and Applications BWB
Enclosure:
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ATTACHMENT 2 TECHNICAL EVALUATION LETTER i.
OF THE SECOND 10-YEAR INTERVAL INSERVICE INSPECTION REQUEST FOR RELIEF NUMBER 19 FOR FLORIDA POWER AND LIGHT COMPANY ST. LUCIE NUCLEAR PLANT, UNIT 2 DOCKET NUMBER:
50-389
1.0 INTRODUCTION
4 The licensee, Florida Power and Light Company (FPL), submitted Request for
' l Relief Number 18, for the second 10-year inservice inspection (ISI) interval, in a letter dated October 15, 1993. The Idaho National Engineering Laboratory (INEL) has evaluated the subject request for relief in the following sections.
2.0 EVALVAT103 The Code of record for the St. Lucie Nuclear Plant, Unit 2, second 10-year inservice inspection (ISI) interval, which began August 8, 1993, is the 1989 Edition. The information provided by the licensee in support of a request for relief from impractical requirements has been evaluated and the bases for granting relief from those requirements are documented below.
l The evaluation of Relief Request Number 18 has been divided into four subject areas. The licensee provided an all inclusive " Basis For Relief" and j
" Alternative Examinations or Tests" under Parts D and E of their submittal.
For purposes of the evaluation, the four subjects are addressed independently, using applicable paragraphs from the " Basis For Relief" and " Alternative 4
Examinations or Tests".
A.
Relief Reauest Number 18 (Part A). Paraaraoh IWA-5242(a). Visual Examination of Insulated Components Code Reauirement:
Paragraph IWA-5242(a) requires that, for systems borated for the purpose of controlling reactivity, insulation shall be 1
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i removed from pressure-retaining bolted connections for VT-2 visual examination.
Licensee's Code Relief Reauest: The licensee requested relief from the I
j removal of insulation on pressure-retaining bolted connections in borated l
systems for the sole purpose of VT-2 visual examination during system j
pressure testing as required by IWA-5242(a).
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l Licensee's Basis for Reauestina Relief (as stated):
.I "For systems borated for the purpose of controlling reactivity, the ii requirement to remove insulation from pressw? retaining. bolted connections for visual examination VT-2, assumes that the only time these systems are examined is during a Code required pressure test.
l "The IWA-5242 requirement does not take into consideration any additional, and more frequent visual examinations, such as (1) Technical i
Specification surveillance requirements; (2) preventative maintenance activities; (3) system walkdowns; and (4) repairs and/or replacement 4
i activities, for which, the majority of these additional visual examinations are performed. To a large extent, these additional visual i
examinations are performed when the system is in-service.
"IWA-5242(a), (b), and (c) provide enough direction for performing visual examinations on insulated components, whether the pressure retaining bolted connection is located in a borated line or not.
"In addition to the above requirements, FPL is implementing ASME Code Case N-498 for all Class 1 and 2 pressure retaining components. This code case allows in lieu of the hydrostatic pressure test, the use of a -
system leakage test at or near the end of the inspection interval. As a condition _to the use of this code case, the hold time for insulated components is upgraded from essentially no hold time to a four hour hold time.
"FPL feels that' the four hour hold time will be more _ than adequate for
- the examination of insulated components, and substantially increase the i
. assurance of identifying leakage during the conduct of a system pressure test without the removal of insulation..
"IWA-5250 (a) also requires FPL to locate the source of leakage detected during the conduct'of a system pressure test.
Locating the source of i
leakage will in most cases require the removal of the insulation.
"The removal of insulation on each pressure retaining bolted connection will require a significant expenditure of manpower for the erection of scaffolding, the removal and the reinstallation of insulation following performance of the pressure test and examination.
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"This additional manpower,'not to mention, the increase in radiation exposure (man maintenance c/ rem), will contribute significantly to the operations and l
t quality or safety of the unit,osts without any substantial coirpensating increase i
"The additional cos (man / rem),........ts, manpower expenditures, and radiation exposure
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quality of the examination / test, nor in the safety' of the' unit.",
a Licensee's Pronosed Alternative Examination (as stated):
,t bolted connections, when determined by evaluation t insulation is warranted, or when leakage to be identified during a system
.!q pressure test that requires the source of the leakage to be identified in 4 -
accordance with IWA-5250.
evaluation process ma The decision to remove insulation during the historical leakage; (y be based on (a) type and location of leakage; (b) i c) construction materials of the leaking component; (d) visual evidence of corrosion; (e) corrosiveness of process fluid; and (f) the bolt material degradation history due to corrosion in a similar environment."
9 Evaluation:
Paragraph IWA-5242(a) requires the removal of insulation i
from pressure-retaining bolted connections in borated systems for direct 3
VT-2 visual examination during system pressure testing.
The licensee implies that insulation removal for direct VT-2 visual examination of j
bolted connections is a hardship.
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'Recent incidences of degraded bolting have reinforced the requirement to remove insulation at bolted connections when performing the VT-2 visual
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examinations (
Reference:
Event Report Numbers 26899 dated 3/8/94, and i
26992 dated 3/25/94).
Because degradation rates cannot be reliably
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predicted and bolting material records may not be accurate, the direct visual examination and immediate corrective action for leakage at bolted j
i connections is warranted.
Therefore, based on the referenced incidences of degraded bolting, it is recommended.that relief be denied.
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B.
Relief Reauest Nvmber 18 (Part B). IWA-5250(a)(2). Corrective Measures for Leakaoe at Bolted Connections U de_R auiremeg :
Paragraph IWA-5250(a)(2) requires that if leakage f
occurs at a bolted connection, the bolting shall be removed, VT-3 visually examined for corrosion. and evaluated in accordance with IWA-3100.
Licensee's Code Relief Reauest: The licensee requested relief from removal of all pressure-retaining bolting from a bolted connection wnen leakage is observed during a system pressure test, as required by IWA-5250(a)(2).
Licensee's Basis for Reauestina Relief (as stated):
"The removal of all pressure retaining bolting from a bolted connection solely because leakage was observed during a system pressure test is impractical. This requirement dces iut take in consideratior (1) the type and location of leakage; (2) hisWical leakage; (3) construction material of the leaking component; (4) corrosiveness of process fluid; and (5) the bolting material degradation history due to corrosion in a similar environment.
"In addition to the considerations (1) through (5) above, this requirement does not take into account the results of previous inspections, examination, tests,and/or previous corrective actions taken. This requirement restricts FPL from performing an evaluation of the condition (s) based on actual facts / data, and to implement corrective action based on the actual severity of the evaluation as allowed under Section XI.
"IWA-5250(a)(2) was changed in the 1992 Edition of Section XI, to require only one of the bolts to be removed, if leakage occurs at a bolted connection.
"The additional costs, manpower expenditures, and radiation exposure (man / rem),........, do not provide any compensating increase in the quality of the examination / test, nor in the safety of the unit."
Licensee's Prooosed AM ernat W Mamination (as stated):
I "If the evalcation process indicates that the pre are retaining bolting is not susceptible to corrosion, removal of bolti.g will not be required.
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i A.
"If the evaluation process indicates that the pressure retaining bolting may be susceptible to corrosion and requires removal, the bolt closest to the source of leakage shall be removed.
"When the visual examination VT-1 is required and leakage is identified on a pressure retaining bolted connection that is in service, and the evaluation justifies continued service, the removal of a pressure retaining bolt for visual examination VT-1 may be deferred to the next 4
time the system is out of service, but no later than the next refueling outage.
"When the egradation of a removed pressure retaining cult exceeds FPL acceptance criteria and the evaluation determines that the bolting is susceptible to corrosion, all remaining pressure retaining bolting shall be removed. A visual examination VT-1 shall be performed and the results of the examination shall be compared against the acceptance criteria of IWB-3517.1."
Evaluation:
In accordance with the 1989 Edition of the Code, when 4
leakage occurs at a bolted connection during the conduct of a system pressure test, all bolting is required to be removed for VT-3 visual examination. The licensee has proposed to perform an evaluation of the leakage and bolting in bolted connactions to determine if the removal of bolting may be deferred until the npt refueling outage, at which time the bolting would be removed and examined.
In addition, the licensee has proposed to perform a VT-1 visual examination as part of the evaluation l
in lieu of the VT-3 visual examination.
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i The licensee's alternative VT-1 visual examination in lieu of the Code required VT-3 visual examination is considered acceptable because the j-VT-1 visual examination is considered more stringent and has clearer acceptance criteria. However, the evaluation of the bolted connection without the removal of at least one bolt nearest the source of leakage as part of the evaluation should not be considered acceptable.
The licensee's proposed alternative to the removal of bolting when leakage is discovered is not sufficient. However, the removal of at least one bolt for evaluation should detect degradation, if presat.
This approa:h in combination with a VT-1 visual examination should provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), it is recommended that relief be authorized 5
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'd provided the licensee remove at least one bolt, nearest the source of leakage, for a VT-1 visual examination as part of the evaluation.
C.
Relief Reouest Number 18 (Part C). IWA-5250f a)(2). Visual Examination Reouirements Associated With Corrective Measures if leakaoe Occurs at a Bolted Connection Code Reouirement:
IWA-5250(a)(2) requires that if leakage occurs at a bolted connection, the bolting shall be r(
ed, VT-3 visually examined for corrosion, and evaluated in accordance with IWA-3100.
d Licensee's Code Relief Recuest: The licensee requested relief from performing a VT-3 visual examination of bolting removed from bolted connections where leakage occurred.
Licensee's Basis for Reouestino Relief (as stated):
"The performance of a visual examination VT-3 for evidence of corrosion on pressure retaining bolting is impractical, since Section XI consistently references the visual examination VT-1 for pressure retaining bolting. FPL procedures were written to use the acceptance criteria for VT-1 examinations of bolting. The VT-3 examination does not provide adequate acceptance criteria for pressure retaining bolting. The additional cost of revising the test, visual examination, and inspection procedures solely for the purpose of changing the VT-1 examination to VT-3 is impractical.
'"The dditional costs, manpower expenditures, and radiation exposure (man / rem),........, do not provide any compensating increase in the quality of the examination / test, nor in the safety of the unit."
Licensee's Proposed Alternative Examination (as stated):
"A visual examination VT-1 shall be performed in accordance with IWA-2211, in lieu of the visual examination VT-3.
The results of the examination shall be compared against the acceptance criteria of IWB-3517.1.
"The evaluation and the visual examination VT-1 documentation shall he traceable to the visual examination VT-2 record."
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a.
Evaluation:
Paragraph IWA-5250(a)(2), requires a VT-3 visual examination of the bolting for corrosion as part of the corrective action when leakage occurs at bolted connection during the conduct of a system pressure test. Table IWB-2500-1, Examination Categories B-G-1 and B-G-2, require a VT-1 visual examination for inservice examinations. The licensee has developed the FPL inspection procedure for bolting visual examinations to comply with VT-1 visual examination requirements.
The licensee has proposed a VT-1 visual examination in accordance with IWA-2211, in lieu of the VT-3 visual examination specified for bolting removed from joints that exhibit leakage. Based on a review of the Code requirements, it has been determined that the VT-1 examination of bolting r.7vides more stringent examination requirements and clearer acceptance criteria. As a result, the VT-1 visual examination will provide an acceptable level of quality and safety when such examinations are required. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), it is recommended that the proposed alternative be authorized.
D.
Relief Reauest Number 18 (Part D). IWA-5261. Tvoe of Instruments Used for Pressure Tests Code Reauirement:
Paragraph IWA-5261, requires that any " Type" pressure measuring instrument or sensor, analog or digital, including the pressure measuring instrument of the normal operating system instrumentation (such as control room instruments), may be.used, provided the requirements of IWA-5260 are met (i.e. instrument " Accuracy", " Calibration", " Ranges",
and " Location").
Licensee's Code Relief Reouest: The licensee requested relief from the requirements of IWA-5261 and the associated requirements of IWA-5260,
" Instruments For Pressure Tests" for normal operating system instrumentation (such as control room instruments) when used for system pressure testing.
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Y' Licensee's Basis for Reauestina Relief (as stated):
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"The additional instrumentation requirements for accuracy, calibration, range, and location, defined in IWA-5260 are intended for hydrostatic
'i pressure test, where the pressures and temperatures could, without proper controls, encroach on specific design criteria. To invoke these requirements on normal operating system pressure and temperature instrumentation (such as control room instruments is impractical.
"The 1992 Edition of Section XI corrected this requirement, by changing the title of IWA-5260 to " Instruments for System Hydrostatic Tests."
"The additional ccsts, manpower expenditures, and radiation exposure (man / rem),........, do not provide any compensating increase in.he quality of the examination / test, nor in the safety of the unit."
Licensee's Proposed Alternative Examination:
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The licensee provided no alternatives for the subject Code requirement.
Evaluation: The Code requires that test equipment used for pressure tests meet the criteria stated in IWA-5260. The criteria contained in IWA-5260 includes accuracy, calibration requirements, ranges, and locations for test instruments. The licensee has proposed, as an alternative, to use installed plant instrumentation, which is cr.librated i
and maintained in accordance with plant procedures, to perform system pressure tests.
To ensure that systems are not challenged by pressure tests at elevated pressures or temperatures, instrument accuracy is imperative and tests of instrument accuracy in such cases should be performed. However, for pressure tests at normal operating pressure, using instrumentation calibrated and maintained in accordance with plant procedures should provide 2n acceptable level of quality and safety.
Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), it is recommended that the proposed alternative be authorized provided that the licensee meet the requirements of IWA-5260 for any pressure tests performed at pressures or temperatures exceeding nominal operating pressure.
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3.0 CONCLUSION
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The INEL staff has reviewed the licensee's Request for Relief Number 18 and concludes that the proposed alternative provided in Part C of the evaluation provides an acceptable level of quality and safety and, therefore, pursuant to q
10 CFR 50.55a(a)(3)(1), it is recommended that the proposed alternatives be j
authorized.
For requests for relief in Part 8 and D of the evaluation, it has been determined that the proposed alternatives in combination with the conditions l
stated in the evaluation will provide an accept,able level of quality and j
4 safety and, therefore, pursuant to 10 CFR 50.55a(a)(3)(i), it is recommended that the proposed alternatives be authorized with the conditions stated.
Based on the recent incidences of degraded bolting and that the degradation rates cannot be reliably predicted, it is recommended that Part A of this evaluation be denied.
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