ML20002D992
| ML20002D992 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 09/29/1971 |
| From: | Haueter R, Sewell R, Zabritski J CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | |
| Shared Package | |
| ML20002D991 | List: |
| References | |
| PROC-710929, NUDOCS 8101230756 | |
| Download: ML20002D992 (7) | |
Text
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q Regidatory, File Cy.
BIG ROCK POINT IN-SERVICE INSPECTION PROGRAM
- _T-89-7/
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APPLICABILITY
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This program applies to the in-service structural surveil-lance of components. included within the reactor coolant pressure boundary at the Big Rock Point Nuclear Plant.
OBJECTIVE To insure the integrity of the reactor coolant pressure boundary.
SPECIFICATIONS a.
Postoperational inspections will be made according to the methods and intervals indicated in Section XI of the ASME Boiler and Pressure Vessel Code dated January 1, 1970, except as modified below.
b.
The structural integrity shall be maintained at the level 4
required by original plant acceptance standards throughout the life of the plant. Any evidence obtained as a result of inspections conducted under this program that defects have developed, grown or exceed the original acceptance standards shall be investigated, including evalua-tion of comparable areas of the reactor coolant pressure boundary.
c.
Sufficient records of each inspection shall be kept to allow comparison and evaluation of future tests.
BASIS Pe inapection program implementsSection XI of the ASME Boiler and Pressure Code to the maximum extent practical. It is recognized that plant design and construction was completed approximately seven years prior to the development of Geetion XI and it is therefore not possible to comply fully with code. Areas of exception in the Big Rock Point In-Service Inspection Program are based primarily on experience gained.during the two previous in-service inspections conducted at Big Rock Point Plant prior to the formulation of this program. These exceptions are listed below:
Paragraph IS-211.2 Remote visual examination vill be used for visual inspections.
Depending on the physical arrangement of the area to be inspected, it may 7/o/.2307 %
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or may not be possible to (btain the resolution specified in IS-211.1.
In any circumstance, the best resolution possible should be obtained for the inspection.
Paragraph IS-232 No preoperational examination can be made because the plant has been in operation since 1962. It would also be impractical to attempt an examination of this nature at this. time due to high radiation fields and/or difficulties in gaining access to some areas of the reactor coo' int pres-sure boundary.
Table IS-261 To the extent applicable, based on existing plant design and construction, Thble IS-261 has been followed.
Significant exceptions are as follows:
Item 1.1 - Longitudinal and circumferential welds in core region are not accessible because the outside of reactor vessel is closely surrounded by concrete and access from the inside is not fea-sible due to the proximity of the thermal shield.
Item 1.2 - Longitudinal and circumferential welds in vessel shell are not accessible with existing equipment. Meridional velds in lower head are also not accessible because of core support plate and poor geometry due to hO penetrations.
Item 1 3 - Will attempt to inspect vessel to flange veld from flange sur-face. The veld is 22" below the surface of the flange and attenuation may limit the validity of this inspection.
Item 1.4 - Pritary nozzle to vessel velds are inaccessible due to con-figuration of the vessel internals and/or lack of equipment to perform an inspection of this nature nor does plant design permit inspection of these nozzle welds from the vessel exterior.
Item 1 5 - This item has been deleted with the exception of the control rod drive "J" welds since plant design and present technology do not permit a volumetric examination of this type of penetration.
Item 1.6 - None of the vessel penetrations except closure head penetrations are visually accessible because of plant des _on.
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3 Item 1 7 - A device is being developed to attempt to inspect volumetrically the six reactor vessel steam outlet nozzles primary nozzle to safe-end welds. These welds are not accessible either visually or by surface examination. The two 3" vent nozzles in the re-actor vessel head are accessible for visual and surface inspec--
tions. Previous attempts to inspect these welds volumetrically were unsuccessful due to the physical configuration of the nozzles. All other reactor vessel primary nozzle to safe-end welds are inaccessible because plant design will not allow an
- nspection of this type.
Item 1.12 - This item has been deleted since plant design does not allow access to vessel support pads.
Item 1.15 - The core support plate brackets are not accessible for either direct or remote visual examination due to the physical con-figuration of the reactor vessel.
Item 3 1 - The steam drum longitudinal welds will not be inspected. They are located near the horizontal plane through the center line of the steam drum and are, therefore, inaccessible due to the high radiation field and the inaccessibility of the sides of the steam drum. The circumferential steam drum welds will be inspected only within 30 of are of the top of the steam drum.
Item 3 2 - The steam drum primary nozzle to vessel velds and inside radius sections will not be inspected from the drum exterior due to the high radiation field that exists and the extreme difficulty in removing insulation from the steam drum. The high radiation field that exists inside the drus precludes inspection from the interior.
Item 3 3 - The safe-end to nozzle veld on the steam drum vent line will not be inspected volumetrically because its geometry is such that it does not allow proper placement of an ultrasonic probe, based upon past experience.
Item 3 6 - The entire inspection of steam drum integrally welded supports will be concentrated on the upper supports due to the extremely high radiation area under the steam drum.
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. Item 4.1 - The fcilowing safe-end to pipe and carbon steel to stainless steel transition velds will not be inspected due to the plant physical layout and/or high radiation areas:
Transition welds:
6" shutdown system outlet line.
4" core spray line.
Safe-end to pipe veld:
Reactor vescel recirculating inlet nozzles.
Reactor vessel instrument nozzles.
Reactor vessel emergency coclant inlet nozzle.
Reactor vessel unloading out1st nozzle.
Reactor vessel poison inlet nozzle.
Steam drum vent nozzle - will inspect visually and surface, not volumetric (refer to Item 3 3).
Reactor vessel steam outlet nozzles - will inspect volumetrically only.
Item 4.2 - The longitudinal velds on the main recirculating system steam risers are inaccessible due to plant design and high radiation area.
Circumferential velds in portions of the various systems that comprise the reactor coolant pressure boundary are inaccessible due to plant physical design and/or high radiation fields.
These systems and the approximate percent of inaccessible welds are listed below:
Total Welds Percent System (Approximate)
Inaccessible (Approximate)
Main Steam 51 38%
Feedwater 55 18%
Emergency Condenser 52 15%
Cleanup 159 23%
Shutdown L3 19%
Main Recirculating 102 28%
Core Spray (OriginalSystem) 16 25%
Poison 69 35%
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As further experience is icined in'the in-service inspection program, these numbers may vary slightly.
In any case, Consumers Power Company will make every attempt to inspect the welds classified accessible, " accessible" being defined' later in this document.-
Item 4 5 - Approximately 50% of the integrally welded pipe supports on the main recirculating system ara inaccessible due to physical location and high radiation areas and will not be inspected.
Item 4.6 - The piping restraints on the downeomers will not be inspected due to physical plant layout.
In general, accessibility is limited by plant physical restraints or the necessity to construct platforms, scaffolding, etc, in high radia-tion areas. Accessibility is considered adequate if it is necessary to build a platform in an aret of low radiation or if an item to be inspected is located in a high-radiation area but access is available without con-struction of a working platform. The judgments of accessible or inacces-sible were based on the criteria above and the total man dosc chat might be obtained in performing an inspection.
The frequency of inspection shall be in accordance with Section XI of the ASME Boiler and Pressure Vessel Code.
The percentage basis of the code will be applied to total system items rather than total accessible system items. For example, a system that requires 25% inspection per in-terval that contains 80 welds, 40 of which are considered accessible, would be inspected as follows:
Inspection Interval Welds Inspected 1
First25%
2 Second25%
3 RepeatFirst25%
4 Repeat Second 25%
Effective Date J
For planning and record purposes, this program will be placed in affect on January 1, 1972 and remain in effect until it is superseded.
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6 The pro 6 ram will be reviewed by Consumers Power Company personnel following
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each in-service inspection performed and changes made as appropriate.
Submitted by:
bibk4 kN F
(/ f <WJ'.
Zabritski R.' B. Sewell Approved by:
'Ge'f r s D
i R. L. Haueter I
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