ML20040A487
| ML20040A487 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 01/12/1982 |
| From: | CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | |
| Shared Package | |
| ML20040A484 | List: |
| References | |
| NUDOCS 8201210174 | |
| Download: ML20040A487 (5) | |
Text
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3.23 MECilANICAL SNUBBERS APPLICABILITY:
This specification applies to all mechanical snubbers listed in Table 3.23-1 classified as snubbers installed on safety related systems whose structural integrity is needed to be maintained during and following a seismic or other event initiating dynamic loads.
OBJECTIVE:
To assure reactor coolant system and other safety related systems motions are adequately restricted should a design basis earthquake or other transient occur.
SPECIFICATION:
(a) During modes 1, 2, 3 and 4 all mechanical snubbers listed in Table 3.23-1 shall be operable except as noted in 3-23.(c) through (d).
(b) During modes 1, 2, 3, 4, 5 and 6 the mechanical snubbers on the residual heat removal system shall be operable except as noted in 3.23.(c) through (d).
(c)
From and after the time that a mechanical snubber is determined to be inoperable, within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> replace or restore the inoperable snubbers to operable status and perform an engineering evaluation on the components which are supported by the snubber. The purpose of this engineering evaluation shall be to determine if the component supported by the snubber was adversely affected by the inoperability of the snubber in order to ensure that the supported component remains capable of meeting the design service.
If the snubber cannot be returned to service within the 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, commence an orderly shutdown and within the next 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> be in cold shutdown.
In addition to the conditions of 3.23.(c) above, (d)
If a mechanical snubber is determined to be inoperabic while in mode 3, 4, 5 or 6 the snubber shall be made operable before proceeding to the next mode toward mode 1.
(e) Mechanical snubbers may be added to or deleted f rom safety related systems without prior license amendment to Table 3.23-1 provided that a revision to Table 3.23-1 is included with the next license amendment request.
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TABLE:
3.23-1 CYAPC0 SAFETY RELATED MECHANICAL SNUBBER LIMIT MODEL SYSTEM HANGER #
DRAWING LOCATION ACCESSIBILITY
- PSA 4 RV & Pzr. Vent C7 20234 Containment A
PSA 1 RV & Pzr. Vent C11 20234 Containment B
PSA 4 RV & Pzr. Vent C22 (X-Dir) 20236 Containment A
PSA 4 RV & Pzr. Vent C22 (Z-Dir) 20236 Containment A
PSA 4 RV & Pzr. Vent P2 20235 Containment A
PSA &
RV & Pzr. Vent P5 20235 Containment A
PSA 1 RV & Pzr. Vent P10 20235 Containment A
PSA i CVCS (Boric Acid)
R3 CAT-SK-5-77-615-1805 PAB A
PSA 4 CVCS (Boric Acid)
R4 CAT-SK-5-77-615-1805 PAB A
CLL-PS-10 20231SH103ASA PAB B
PSA 3 RHR HSS-1006A 20231SH105D PAB A, C PSA 3 RHR HSS-1006B 20231SH105D PAB A, C PSA 35 Feedwater PSSP-001 202315H102Q Containment B, C PSA 35 Feedwater PSSP-002 20231SH102Q Containment B, C PSA 35 Feedwater PSSP-011 20231SH102R Containment B, C PSA 35 Feedwater PSSP-012 20231SH102R Containment B, C PSA 35 Feedwater PSSP-015 20231SH102N Containment B,C.
PSA 35 Feedwater PSSP-016 20231SH102N Containment B, C PSA 35 Feedwater PSSP-006 20231SH102P Containment B, C PSA 35 Feedwater PSSP-007 20231SH102P Containment B, C PSA 1 RC Loop Drain PS-1 22079 Containment B
PSA L RC Loop Drain PS-3 22079 Containment B
PSA 4 RC Loop Drain PS-5 22079 Containment B
PSA 4 RC Loop Drain PS-6 22079 Containment 9
PSA 4 RC Loop Drain PS-8 22079 Containment 0
PSA &
RC Loop Drain PS-10 22079 Containment 3
PSA 3 Pzr. Safety & Re1.
240 TDYNE 2726-D4331 Containment A
PSA 3 Pzr. Safety & Rel.
342 TDYNE 2726-D4331 Containment A
PSA 3 Pzr. Safety & Rel.
348 TDYNE 2726-04331 Containment A
PSA 3 Pzr. Safety & Rel.
448 TDYNE 2726-D4331 Containment A
PSA 3 Pzr. Safety & Rel.
631 TDYNE 2726-D4331 Containment A
PSA 3 Pzr. Safety & Re1.
673 TDYNE 2726-D4331 Containment A
PSA 10 Pzr. Safety & Rel.
86 TDYNE 2726-D4331 Containment B, C PSA 10 Pzr. Safety & Rel.
133 TDYNE 2726-D4331 Containment A
- A = Accessible During Reactor Operation B = Reactor Shutdown Required for Access C = Scaffolding or Other Preparations Required for Access 3-50
4.16 MECilANICAL SNU1513ERS APPLICAI5ILITY:
This specification applies to all mechanical snubbers listed in Table 3.23-1 classified as snubbers installed on safety related systems whose structural integrity is needed to be maintained during and following a seismic or other event initiating dynamic loads.
OILIECTIVP. :
To provide assurance of mechanical snubber operability over the plant service lifetime.
SPECIFICATION:
(n) All mechanical snubbers listed in Table 3.23-1 shall be visually inspected to determine that there are no visible indications of damage or impaired operability. Also to check that attachments to the foundation or supporting structure are secure.
Snubbers which appear to be inoperable as a result of visual inspection shall be stroke tested as per (b).
If the stroke test determines that the snubber is operable it need not be counted as a failure in determining future inspection frequency.
All mechanical snubbers shall be visually inspected in accordance with the following schedule-i
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Snubbers are categorized in two groups " Accessible or inaccessible" based on their accessibility for inspection during reactor operation".
Schedule Al - Accessible Number of Snuhbers Found Inoperable During Inspection Next Required Or During Inspection Interval Inspection Interval 0
18 months i 25%
1 12 months i 25%
2 6 months i 25%
3, 4 124 days 1 25%
l 5, 6, 7 62 days i 25%
>8 31 days i 25%
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a The required inspection interval shall not be lengthened more than one step at a time.
Schedule A-II - Inaccessible Snubbers shall be inspected during each refueling.
(b)
All mechanical snubbers listed in Table 3.23-1 shall be stroke tested in accordance with the following schedule at refueling intervals.
One model PSA 3 from the reactor vessel and pressurizer vent system.
One model PSA 3 from the boric acid system.
One model PSA 3 either from the charging system or residual heat removal system.
Two model PSA 35 from the feedwater system.
One model PSA i from the reactor coolant loop drain system.
One model PSA 3 and one model PSA 10 from, the pressurizer safety & relief system.
These stroke tests shall be rotated so that different snubbers are tested at each interval until all snubbers in a category are tested.
If a snubber does not pass the stroke test an additional snubber in that category shall be so tested until no additional failures are found or all snubbers in that category have been tested.
The mechanical snubber stroke test shall verify that:
There is freedom of movement over the full length in both directions.
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BASES:
Mechanical Snubbers All snubbers are required OPERABLE to ensure that the structural integrity of the reactor coolant system and all other safety related systems is maintained during and following a seismic or other event initiating dynamic loads. Snubbers excluded from this inspection program are those installed on nonsafety-related systems and then only if their failure or failure of the system on which they are installed, would have no adverse effect on any safety-related system.
The visual inspection frequency is based upon maintaining a constant level of snubber protection to systems. Therefore, the required inspection interval varies inversely with the observed snubber failure and is determined by the number of inoperable snubbers found during an inspection.
Inspections performed before that interval has elapsed may be used as a new reference point to determine the next inspection, llowever, the results of such early inspections performed before the original required time interval has elapsed (nominal time less 25%) may not be used to lengthen the required inspection inte rval. Any inspection whose results require a shorter inspection interval will override the previous schedule.
When the cause of the rejection of a snubber is clearly established and remedied for that snabber and for any other snubbers that may be generically susceptible, and verified by inservice functional testing, that snubber may be exempted from being counted as inoperable. Generically susceptible snubbers are those which are of a specific make or model and have the same design features directly related to rejection of the snubber by visual inspection, or are similarly located or exposed to the same environmental conditions such as temperature, radiation, and vibration.
When a snubber is found inoperable, an engineering evaluation is performed, in addition to the determination of the snubber mode of failure, in order to determine if any safety-related component or system has been adversely affected by the inoperability of the snubber. The engineering evaluation shall determine whether or not the snubber mode of failure has imparted a significant effect or degradation on the supported component or system.
To provide assurance of snubber functional reliability, a representative sample of the installed snubbers will be functionally tested during plant shutdowns at 18 month intervals.
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