ML19317G987
| ML19317G987 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 08/07/1975 |
| From: | SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | |
| Shared Package | |
| ML19317G982 | List: |
| References | |
| NUDOCS 8004020647 | |
| Download: ML19317G987 (5) | |
Text
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RANCHO SECO UNIT 1 TECHNICAL SPECIFICATIONS -b 4.14 SAFETY SYSTEMS HYDRAULIC SNUBBERS Applicability The following surveillance requirements apply to hydraulic.. snubbers listed in Table 4.14-1.
Objective To verify that the hydraulic snubbers will perform their design. function.
Specification 1.
All hydraulic snubbers whose seal material has been d.:monstrated by operating experience, laboratory testing or analysis to be comoatible with the operating environment shall be visually inspected to verify their ope'rabi1ity in accordance with the foilowing schedule:
Number of Snubbers Found inoperable-during inspection Next Required or during Inspection Interval inspection interval 0
18 months + 25%
1 12 months + 25%
2 6 months T 25%
3, 4 4 months T 25%
'5, 6, 7 2 months T 25%
>8 1 month {25%
The required inspection interval shall not be lengthened more than one step at a time.
Snubbers are catagorized in two groups, " accessible" or " inaccessible" during reactor operation.
These two groups are inspected independently according to the above schedule.
2.
The initial inspection shall be performed within 6 months from the date of issuance of these specifications.
For the purpose of entering the schedule in Specification 4.14.1, it shall be assumed that the facili ty had been on a 6 month inspection.
3.
All hydraulic. snubbers whose seal materials have not been demonstrated to be compatible with the operating environment shall be visually inspected for operability monthly.
4.
At each refueling interval, at least one unit containing ethelene pro-j pylene seals and one unit containing polyurethane seals, which are
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exposed to the most adverse environment (radiation and temperatures),
i shall be disassembled and seal material physical properties evaluated.
If physical properties noted indicate seals are approaching end of useful life, as recommended by snubber manufacturer, all seals in units in a 8004020 b 2 4-47
similar atmosphere'shall be replaced not 1ater than the next refusling
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-Interval. :In addition, if seal' replacement is necessary, per above-requirements, sample units from areas having less' harsh environment shall be disassembled and need for seal replacement determined.
~ BASES:
Hydraulic Snubbers Snubbers are designed to prevent unre-trai aed pipe. motion under dynamic loads es;might occur during an earthquake or seiere transient, while allowing normal.
thermal motion during startup and shutdowr.
The consequence of an inoperable snubber is an increase in the probability of structural damage to piping as a result of a seismic or other event initiating dynamic loads.
It is therefore required that all hydraulic snubbers required to protect the primary coolant system or any other safety ' system or component be operable during reactor operation.
All safety related hydraulic snubbers are visually inspected for overall in-tegrity and operability.
The inspection will include verification of proper orientation, adequate hydraulic fluid level and proper attachment of snubber to piping and structures.
The inspection frequency is based upon maintaining a constant level of snubber protection.
Thus the required inspection interval varies inversely with the observed snubber failures. The number of inoperable snubbers found during a required inspection determines the time interval for the next required inspection.
Inspections performed before that interval has elapsed may be used as a new reference point to determine the next inspection.
However, 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 inspec-tion interval.
Any inspection whose results require a shorter inspection interval will override the previous schedule.
Experience at operating facilities has shown that the required surveillance program should assure an acceptable level of snubber performance provided that the seal materials are compatible with the operating environment.
Snubbers containing seal material which has not been demonstrated by operating experience, lab tests, or analysis to be compatible with the operating environment should be inspected more frequently (every month) until material compatibility is confirmed or an appropriate changeout is completed.
Examination of defective snubbers at reactor facilities' and material tests per-formed at several laboratories (Reference 1) has shown that millable gum poly-urethane deteriorates rapidly under the temperature and moisture conditions present in many snubber locations.
Although molded polyurethane exhibits greater resistance to these conditions, it also may be unsuitable for application in the higher temperature environments.
Data are not currently available to precisely define an upper temperature limit for the molded polyurethane.
Lab tests and in plant experience indicate that seal materials are available, primarily ethylene propylene compounds, which should give satisfactory performance under the most severe conditions expected in reactor installations.
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Te furth2r incrdsse th2 'essur:nca cf snubb:r reliability, tcsts Lshould be per-
' formedLonce each refueling cycle.
These tests will' include disassembling to verify ~ proper seal integrity.
Observed failurcs on these samples should' require testing of additional ounits.
Snubbers indhigh radiation areas or those especially difficult to remove need not' be selected for tests provided operability ws ;
previously verified. To complement the visual external inspections, disassembly; and Internal examination for component damage and abnormal seal degradation should be performed.
The' examination of two units,:cach refueling cycle, selected from relatively severe environments should adequately' serve this-purpose. Any
- observed wear, breakdown or deterioration will provide a basis for cdditional inspections.
4 (1)
Report H. R. Erickson, Bergen Paterson to K. R. Goller, NRC, October 7, 1974
Subject:
Hydraulic Shock Sway Arrestors 4-47b
L TABLE 4.14-1L Snubbers Accessible Dtiring -Power. Operatior.s L List No.
-I.D.~No.
-List No.
-I.D. No.
1 MS 20528 SW 1-30 c4SW.20024-3A
-2 MS 20521 SW 11' 31:
4SW-26101 3 MS 205'20 SW 3-32 4SW 26101-6~
4J MS-20521 SW 13 33:
4SW 25023-5A 5
MS 20520 SW 5-34 4SW 26101-8A 6
MS 20521'SW.14 35 4SW-25023-8A.
7-MS 20520 SW 13A 36 4SW 26100-3 8
MS 20520 SW 6 37 l4SW 26100-1A1 9
MS 20526 SW 9 38 4SW 26022-13A 10 9SW 30709-3A' 39 4SW 26025-43 11-9SW 30708-4 40 4SW 23620-3A 12 9SW 30708-5A' 41 4SW 53520-3 13 9SW 30709-4 42 4SW 29101-1A 14 9SW 30709-3 101
-MS 20520 SW 19 15 SSW 20530-7A 102
~MS 20521 SW 20 16 SSW 20529-3A
-103 MS 20521 SW 22
-17 SSW 53520-3 104 MS 20520 SW 21 18 5SW 32141-1A 105 1C SW 20553-1A 19 5SW 32141-2 106 SSW 20529-1A 20 10 SW 20530-3A
-107 SSW 20529-4A 21 12 SW 20530-3A 108 5SW 20530-8 22 7SW 32120-1B 109 7SW 30800-6 23 7SW 32120-1A 110 7SW 30800-8 24 7SW 32120-1C 111 7 SW 30800-12 25 MS 20550 SU 1 112 7SW 30800-14 26 MS 20558 SW 1 113 75W 30804-1 27 MS 20532 SW 1 114 7SW 30805-2 28 MS 20531 SW 1 115 SSW 23803-4A 29 7SW 32140-2 116 4SW 60014-4A 4
4-47c n
c
.. : * :?.
TABLE 4.14-l'
' Snubbers Inaccessible'During Power Operations Litt No.
I.D. No.
List No.
I.D. No.
PS 1 SW 1CP B&W-5 125 1 SW 21021-3~
P6 1.SW 10 B&W-6 126 1 SW 23823-7A P7 1 SW.10" B&W-7 127' 11 SW 21025-9A 50 1 SW 20025-3 128 1 SW 21005 51 1 SW 20025-1A' 129 1 SW 23822-7B 52
~1 SW 26020-5A 130
-1 SW 21028-2 53 1 SW 26524-4A 131-1 SW.26020-6A 54 1 SW 50060-8A 132 1 SW 20082-12A 55 1 SW 22000-9 133 1-SW 26521-2A.
56 1 SW 26021-5A 134 1 SW 21025-6 57 1 SW 26021-7A 135 1 SW 23823-13A 58 1 SW 26021-11A 136
~ 1 SW 21001-20 59 1 SW 50063-2A 137 1 SW 21001-28 60 1 SW 23823-8 138 1 SW 50050-6A.
61 1 SW 23620-15A SS-1 SS-1 62 1 SW 23626-3A SS-2 SS-2 63 1 SW 29122-28A SS-3 SS-3 64 1 SW 29125-7A SS-4 SS-4 65 1 SW 29125-7C SS-5 SS-5 66 MS 20523 SW2 SS-6 SS-6 67 MS 20521 SW17 SS-7 SS-7 68 1 SW 21925-9A SS-8 SS-8 69 1 SW 50050-2A SS-9 SS-9 70 MS 20520 SW 18 SS-10 SS-10 71 MS 20522 SW2 SS SS-11 72 1 SW 50060-3A SS-12 SS-12 73 1 SW 32140-4 SS-13 SS-13 74 1 SW 32140-2 SS-14 SS-14 75 1 SW 32141-4 SS-15 SS-15 76 1 SW 32141-2 SS-16 SS-16 77 1 SW 50053-2A SS-17 SS-17
-117 1 StJ 22000-12 SS-18 SS-18 118 1 SW 22000-2A SS-19 SS-19 119 1 SW 22001-2 SS-20 SS-20 120 1 SW 21007-7 SS-21 SS-21 121 1 SW 21022-5 SS-22 SS-22 122 1 SW 21006-6A SS-23 SS-23 123 1 SW 23626-1A SS-24 SS-24 124 1 SW 21022-1 4-47d
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