ML20082Q991
| ML20082Q991 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 09/10/1991 |
| From: | Hebdon F Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20082Q994 | List: |
| References | |
| GL-90-09, GL-90-9, NUDOCS 9109130163 | |
| Download: ML20082Q991 (21) | |
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W ASHINoTON, D.C. 20656 g.....f TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-327 SE000YA4 NUCLEAR PLANT, UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No.153 License No. DPR-77 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by Tennessee Valley Authority (the licensee) dated May 24, 1991, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act).
and the Commission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commissiori; C.
There.is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and F.-
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Conmission's regulations and all applicable requirements have been satisfied.
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. 2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment and paragraph 2.C.(2) of Facility Operating License No. DPR-77 is hereby amended to read as follows:
(2) Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No.153, are hereby incorporated in the license. The licensee shall operate the f acility in accordance with the Technical Specifications.
3.
This license amendment is effective as of its date of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION c],... ;,)i ?,.
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Frederick J. Hebdon, Director Project Directorate 11-4 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of issuance: September 10, 1991
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ATTACHMENT T0 t iCENS~ AMENDMENT NO.153 l
FACILITY OPERAThtG LICL,'GE NO. DPR-77 DOCKET h1 50-327 Revise the Appendix A Technical Specificat'.ons by renoving the pages identified below and inserting the enclosed pages. The revised pages i
are identified by the captioned amendment number and contain marginal lines indicating the area of change.
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REMOVE INSERT 3/4 7-21 3/4 7-21 3/4 7-21a 3/4 7-21b i
3/4 7-22 3/4 7-22 3/4 7-23 3/4 7-23
.i 83/4 7-6 B3/4 ?-6
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3 PLANT SYSTEMS
=3/4.7.9-SNUBBERS r
LIMITING CONDITION FOR-0PERATION l
r 3.7.9.
All safety-related snubbers shall be OPERABLE.
l APPLICABILITY:
MODES 1, 2, 3 and 4.
(MODES 5 and 6 for snubbers located on i
systems or partial systems required OPERABLE in those MODES.)
l ACTION:
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With one or more snubbers 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 snubber (s) to OPERABLE status and,nerform an engineering evaluation on the attached component or declare the attached system inoperable and follow the appropriate ACTION statement for that system.
i SURVEILLANCE REQUIREMENTS 4.7.9.
Each safety related snubber shall be demonstrated OPERABLE by-performance i
of the following au mented inservice inspection program and the requirements of Specification 4.
5.
f a.
Inspection Groups l
The snubbers may be categorized into two major groups based one whether i
the snubbers are accessible or inaccessible during reactor operation.
r These-majorgroupsmaybefurthersubdividedinto'subgroupsbasedon l
design, environment, or other features which may be expected to affect
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the OPERABILITY of the snubbers within the subgroup.
Each subgroup
.may be tested independently in accordance with 4.7.9 d through E
4.'7.9.h.
i-b.
Visual Inspection Schedule and Lot Size All of the safety-related snubbers shall be included in one population or they shall.be categorized as accessible or inaccessible for visual
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inspection.
If used, the accessible or inaccessible categories shall be i
considered separately for visual inspections.
i When recombining categories into one population, the shorter interval of I
the categories shall be used.
l The visual inspection interval for the population or each category shall 7
be determined based upon the criteria provided in Table 4.7.9-1. and the L
first inspection interval determined using this criteria shall be based upon the previous inspection interval as established by the requirements l
in effect before the amendment which incorporated this change was issued l
by the NRC.
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f SEQUOYAH - UNIT 1 3/4 7-21 Amendment No. 39,153
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Table 4.7.9-1 SNUBBER VISUAL INSPECTION INTERVAL NUMBER Of UNACCEPTABLE SNUBBERS Population
. Column A Column B Column C or Category Extended Interval Repeat Interval Reduce Interval (Notes 1 and 2)
(Notes 3 and 6)
(Notes 4 and 6)
(Notes 5 and 6) 1 0
0 1
80 0
0 2
100 0
1 4
150 0
3 8
200 2
5 13 l
300 5
12 25 400 8
18 36 500 12 24 48 750 20 40 78 1000 or greater 29 56 109 Note 1:
The next visual inspection interval for a snubber population or category size shall be determined based upon the previous inspection interval and the number of unacceptable snubbers found during that interval.
Snubbers may be categorized, based upon their accessi-bility during power operation, as accessible or inaccessible.
These categories may be examined separately or jointly.
However, the licensee must make and do ument that decision before any inspection and shall use that decision as the basis upon which to determine the next inspection interval for that category.
Note 2:
Interpolation between population or category size and the number of unacceptable snubbers is permissible.
Use next lower integer for the value of the limit for Columns A, B, or C if that integer includes a fractional value of unacceptable snubbers as described by interpolation.
Note 3:
If the number of unacceptable snobbers is equal to or less than the number in Column A, the next inspection interval may be twice the previous interval but not greater than 48 months.
SEQUOYAH - UNIT 1 3/4 7-?la Amendment No.153 1
e Table 4.7.9-1.(continued)
-SNUBBER VISUAL INSPECTION INTERVAL Note 4:
If-the number unacceptable snubbers is equal to or less than the
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number in Column B but greater than the number in Column A, the next inspection interval shall be the same as the previous interval.
Note 5:
If the number of unacceptable snubbers is equal to or greater than the number in Column C, the next-inspection interval shall be two-thirds of the previous interval.
However, if the number of unaccep-table snubbers is less than the number in Column C but greater-than the number in Column B, the next interval shall be reduced propor-tionally by interpolation, that is, the previous interval shall be reduced by a factor that is one third of the-ratio of the difference-between the number of. unacceptable snubbers found during the previous interval and the number in Column B to the difference in the numbers in Column-B and C.
Note 6:
The provisions of Specification 4.0.2 are applicable for all inspection intervals'up to and including 48 months.
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SEQUOYAH - UNIT 1 3/4 7-21b Amendment No.153 l
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i PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) c.
Visual-Inspection Performance and Evaluation Visual inspections shall verify (1) that there are no visible indications of damage or= impaired OPERABILTY, (2) bolts attaching the snubber to the-foundation or supporting structure are secure, and-(3) snubbers attached to sections 'of safety-related systenis that have experienced unexpected potentially damaging transients since the last inspection period shall be evaluated for the possibility of concealed damage and functionally tested, i
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-if' applicable, to confirm operability, e
I Snubbers which appear inoperable as a result of visual inspections may be determined OPERABLE _for the purpose of establishing the next visual inspection-interval,-providing that (1) tha cause of the rejection is clearly-established and remeaied for that particular. snubber and for other snubbers that may be generically susceptible; and (2).the affected snubber is functionally tested, if applicable, in the as-found condition and. determined OPERABLE per Specification 4.7.9.e.
Hydraulic snubbers with inoperable single or common fluid reservoirs which have uncovered fluid ports shall be declared _ inoperable. When hydraulic snubbers which E
have uncovered fluid ports are tested, the tests shall be performed by i-starting with_the piston at_the as-found setting and extending the piston rod in the extension mode direction.
Also, snubbers which_have been made inoperable as the result of unexpected transients, isolated damage or other such random events, when the provisions F
of 4.7.9.g ar.d 4.7.9.h have been met and any other appropriate corrective action implemented, shall not be counted in determining the next visual inspection interval.
d.
Functional Test Schedule, Lot Size, and Composition During each refueling outage, a representative sample of 10% of the total of the cafety-related snubbers in use in the plant shall be functionally tested either in place or in a bench test.
l SEQUOYAH - UNIT 1 3/4 7-22 Amendment No.12,153
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PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) d.
Functional Test Schedule, Lot Size, and Composition (Continued)
The representative sample selected for functional testing shall include the various configurations, operating environments, and the range of size and capacity of snubbers within the groups or subgroups.
The representative sample should be weighted to include more snubbers from severe service areas such as near heavy equipment.
Unless a failure analysis as required by 4.7.9.f indicates otherwise, the sample shall be a composite based on the ratio of each group to the total number of snubbers installed in the plant.
Snubbers placed in the same location as snubbers which failed the previous functional test shall be included in the next test lot if the failure analysis shows that failure was due to location.
The security of fasteners for attachment of the snubbers to the component and to the snubber anchorage shall be verified on snubbers selected for functional tests.
e.
Functional Test Acceptance Criteria The snubber functional test shall verify that:
1.
Activation (restraining action) is achieved within the specified range in both ter,sion and compression, except that inertia dependent, acceleration limiting mechanical snubbers, may be tested to verify only that activation takes place in both directions of travel.
2, Snubber bleed, or release where required, is present in both tension and compression, within the specified range.
3.
The force required to initiate or maintain motion of the snubber is within the specified range in both directions of travel.
l 4.
For snubbers specifically required not to displace under continuous load, the ability of the snubber to withstand load without displace-ment shall be verified.
5.
Testing methods may be used to measure parameters indirectly or parameters other than those specified if those results can be correlated to the specified parameters through established methods.
f.
Functional Test Failure Analysis and Additional Test Lots If any snubber selected for functional testing either fails to lock up or fails to move due to manufacture or design deficiency, all snubbers of the same design subject to the same defect shall be functionally tested.
SEQUOYAH - UNIT 1 3/4 7-23 Amendment No. 12 153 l
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PLANT SYSTEMS
'l BASES SNUBBERS (Continued) l that may be genecically susceptible and operability verified by inservice func-l tional testing, if applicable, that snubber may be exempted from being counted i
as inoperable.
Generically susceptible snubbers are those which are of a specific make or model and have the same design features directly related to i
rejection of the snubber, or are similarly located or exposed to the same i
environmental conditions such as temperature, radiation, and vibration.
Test groups may be established based on design features and installed conditions which may be expected to be generic.
Each of these groups are tested separately i
unless an engineering analysis indicates the group is improperly constituted.
All suspect snubbers are subject to inspection and testing regardless of test groupings.
To further increase the assurance of snubber reliability, functional tests shall be performed during each refueling outage.
These tests will include stroking of the snubbers to verify proper movement, activation, and bleed or l
release.
The performance of hydraulic snubbers generally depends on a clean, l
deaerated fluid contained within variable pressure chambers, flowing at closely controlled rates.
Since these characteristics-are subject to change with expo-sure to the reactor environment, time, and other factors, their performance within the specified range should be verified.
Mechanical snubbers which depend upon overcoming the inertia of a mass and the braking action of a capstan spring contained within the snubber for limiting the acceleration of the attached compo-nent (within the load rating of the snubber) are not subject to changes in per-formance in the same manner.as hydraulic snubbers.
Pending the development of information regarding the change during the service of the snubber of the acceleration / resistance relationship and the optimum method for detecting this t
change, tnese mechanical snubbers may be tested to verify that when subjected to a large change in velocity the resistance to movement increases greatly.
The performance change information was developed in order to establish test l
methods to be used during and aft.er the first refueling outage.
Ten percent of the total population of snubbers is an adequate sample for l
j functional tests.
The initial sample is to be proportioned among the groups in order to obtain a representative sample.
Observed failures of more than two snubbers in the initial lot will require an engineering analysis and testing of i
additional snubbers selecteo from snubbers likely to have the same defect.
A thorough inspection of the snubber threaded attachments to the pipe or components
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and the anchorage will be made in conjunction with all required functional tests.
3 A list of individual snubbers with detailed information of snubber loca-tion and size shall be available at the plant in accordance with Section 50.71(c) of 10 CFR Part 50.. The accessibility of each snubber shall be determined l
1 based upon the existing radiation ievels and the expected time to perform a visual' inspection in each snubber location as well as other factors associated with accessibility during plant operations (e.g., temperature, atmosphere, P
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SEQUDYAH - UNIT 1 B 3/4 7-6 Amendment No. 39, 153
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UNITED STATES
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i! i NUCLEAR REGULATORY COMMISSION
'o, \\djhj'y%.....,f WASHINoTON, D C. 206M TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-3?8 SEQUOYAH NUCLEAR PLANT, UNIT P AMENDMENT ~0 FACILITY OPERATING LICENSE Amendment No.143 License No. DPR-79 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment tay Tennessee Valley Authority (the licensee) dated May 24, 1991, complies with the standards and requirenents of the /, tom!c Energy Act of 1954, as amended (the Act),
and the Commission's rules and regula. ions set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can-be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.
The issuance of this amendment will not be inimical to the conmon defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
2.
2 2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment and paragraph-2.C.(2) of Facility Operating License No. DPR.79 is hereby amended to read as follows:
(2) Technical Specifications-The Technical Specifications contained in Appendices A and B, as revised through Amendment No.143, are hereby incorporated in the license. The licensee shall-operate the facility in accordance with the Technical Specifications.
3.
This license amendment is effective as of its date of issuance.
FOR THE NOCLEAR REGULATORY COMMISSION n.a Ky 1:1s Frederick J. Hebdon, Director Project Directorate 11-4 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuancei September 10,~ 1991 l
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s ATTACHMENT TO LICENSE AMENDilENT N0.143 FACILITY OPERATING LICENSE N0. DPR-79 DOCKET NO. 50-328 Revise the Appendix A Technical Specifications by removing the pages identified below and inserting the enclosed pages.
The' revised pages are identified by the captiened amendment number and contain marginal lines indicating the area of change. Overleaf pages* are provided to naintain document completeness.
REMOVE INSERT 3/4 7-21 3/4 7-21 3/4 7-21a 3/4 7-21b 3/4 7-22 3/4 7-22 3/4 7-23 3/4 7-23 3/4 7-24 3/4 7-24
- B3/4 7-5
- B3/4 7-5
.B3/4 7-6 B3/4 7-6 83/4 7-6a B3/4 7-6a
s 4-PLANT SYSTEMS 3/4.7.9 SNUBBERS LIMITING CONDITION FOR OPERATION 3.7.9 All safety-related snubbers shall be OPERABLE.
APPLICABILITY:
Modes 1, 2, 3 and 4 (MODES 5 and 6 for snubbers located on systems or partial systems required OPERABLE in those MODES.)
ACTION:
With one or more snubbers 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 snubber (s) to OPERABLE status and perform an engineering evaluation on the attached component or declare the attached system inoperable and follow the appropriate ACTION statement for that system.
SURVEILLANCE REQUIREMENTS 4.7.9 Each safety-related snubber shall be demonstrated OPERABLE by performance of the following augmented inservice inspection program and the requirements of Specification 4.0.5.
a.
Inspection Groups The snubbers may be categorized into two major groups based on whether the snubbers are accessible or inaccessible during reactor operation.
These major groups may be further subdivided into subgroups based on design, environment, or other features which may be expected to-affect the OPERABILITY of the snubbers within the subgroup.
Each subgroup may be tested independently in accordance with 4.7.9.d through 4.7.9.h.
b.
Visual Inspection Schedule All of the safety-related snubbers shall be included in one population or _they shall be categorized as accessible or inaccessible for visual inspection.
If used, the accessible or inaccessible categories shall be considered separately for visual inspections.
When recombining categories 1cto one population, the shorter interval l-of the categories shall be used.
The visual inspection interval for the population or each category L
shall be determined based upon the criteria provided in Table 4.7.9-1, and the first inspection interval determined using this l
criteria shall be based upon the previous inspection interval as established by the requirements in effect before the amendment which L
incomorated this change was issued by the NRC.
SEQUOYAH - UNIT 2 3/4 7-21 Amendment No. 31,143
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Table 4.7.9-1 SNUBBER VISUAL INSPECTION INTERVAL NUMBER OF UNACCEPTABLE $NUBBERS Population Column A Column B Column C or Category Extended Interval Repeat Interval Reduce Interval (Notes 1 and 2)
(Notes 3 and 6)
(Notes 4 and 6)
(Notes 5 and 6) 1 0
0 1
80 0
0 2
1 100 0
1 4
150 0
3 8
200 2
5 13 300 5
12 25 400 8
18 36 500 12 24 48 750 20 40 78 1000 or greater 29 56 109 Note 1:
The next visual inspection interval for a snubber population or category size shall be determined based upon the previous inspection interval and the number of unacceptable snubbers found during that interval.
Snubbers may be categorized, based upon their accessi-bility during power operation, as accessible or inaccessible.
These categories may be examined separately or jointly.
However, the licensee must make and document tLat decision before any inspection and shall use that decision as the basis upon which to determine the next inspection interval for that category.
Note 2:
Interpolation between population or category size and the number of unacceptable snubbers is permissible.
Use next lower integer for the value of the limit for Columns A, B, or C if that integer includes a fractional value of unacceptable snubbers as described by interpolation.
Note 3:
If the number of unacceptable snubbers is equal to or less than the number in Column A, the next inspection interval may be twice the previous interval but not Greater than 48 months.
SEQUOYAH - UNIT 2 3/4 7-21a Amendment No.143
-Table 4.7.9-1 (continued)
SNUBBER VISUAL INSPECTION INTERVAL Note 4:
If the number of unacceptable snubbers is equal to or less,han the number 'in Column B out greater than the number in Column A, the next inspection interval 1shall be the_same as the previous interval.
Note 5:
If_the number of unacceptable snubbers is equal to or greater than the number in Column C, the next inspection inter"al shall be two-thirds of the previous interval.
However, if the number of unaccep-table snubbers is less than the number in Column C but greater than the number in Column B the next interval shall be reduced propor-t tionally by interpolation, that is, the previous interval shall be reduced by a factor that is one third of the ratio of the difference between the number of unacceptable snubbers found during the previous interval and the number in Column B to the difference in the numbers in Column B and C.
Note 6:
The provisions of Specification 4.0.2 are applicable for all inspection intervals up to and including 48 months, r
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i-i SEQUOYAH - UNIT 2 3/4 7-21b Amendment No.143
s PLANT SYS'TEMS SURVEILLANCE REQUIREMENTS (Continued) c.
Visual Inspection Performance and Evaluation Visual inspections shall verify (1) that there are no visible indications of damage or impaired OPERABILITY, (2) bolts attaching the snubber to the foundation or supporting structure are secure, and (3) snubbers attached to sections of safety-related systems that have experienced unexpected potentially damaging transients since the last inspection period shall be evaluated for the possibility of concealed damage and functionally tested, if applicable, to confirm operability.
Snubbers which appear inoperable as a result of visual inspections may be determined OPERABLE for the purpose of establishing the next visual inspection interval, providing that :1) the cause of the rejection is clearly established and remedied for that particular snubber and for other snubbers that may be generically susceptible; and (2) the affected snubber is functionally tested, if applicable, in the as-found condition and determined OPERABLE per Specifica-tion 4.7.9.e.
Hydraulic snubbers with inoperable single or common fluid reservoirs which have uncovered fluid ports shall be declared inoperable.
When hydraulic snubbers which have uncovered fluid ports are tested, the tests shall be performed by starting with the piston at the as-found setting and extending the piston rod in the extension mode direction.
11 SEQUOYAH - UNIT 2 3/4 7-22 Amendment No. 2, 143
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PLANT SY Tem SilRVEILJ NCE REQUIREMENTS (Continued) e b
c.
Visual Inspection Performance and Evaluation (Cont'd)
Also, snubbers which have been made inoperab h as the result of I
unexpected transients, isolated damage or other such random events,
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when the provisions of 4.7.9.g and 4.7.9.h have been met and any y
other appropriate correct ne action implemented, shall not be counted iri determining the next sisual inspection interval, b
d.
Functional 'ast Schedute, Lot Size, and Composition During & i refueling outage, a repre:entative sample of 10% of the a
total of the safety related snubbers in ust 'r %e plant shall be functionally tested either in place or in a r i test.
The representative sample selected for functional testing shali E
include the various configurations, operating environments, and the range of size and capacity of snubbers within the groups or subgroups.
The representative sample should br. weighted to include tr.;re snubbers from severe service areas such as near heavy equipment.
Unless a f ailure analysis as required t".' 4.7 S.f indicates otherwise, the sample shall be a composite based en the ratio of each group to the total number of snubbers installed in the plant.
Snubbers placed in the some location as snubbers which failed the previous functional test shall be included in the next test lot if the failure analysis shows that failure was due to location.
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The security of fasteners for attachment of the wabbers to the component and to the snubber anchorage shall be verified on snubbers selected for functional tests, e.
Functional Test Acceptance Criteria The snubber functional test > hall verify that:
1.
Activation (rostraining action) is achieved within the specified range in both tension and compression, except that inertia F
dependent, acceleration limiting mechenical snubbers, may be testod to verify only that activation taket place in both directions of travel.
2.
Snubber beced, or release where required, is present in both tension and compression, within the specified range.
3.
The force required to initiate or maintain motion of the snubber is withiri the 3pecified range in both directions of travel.
T.
SEQl10YAH - UNIT 2 3/4 7-23 Amendment No. 2, 143
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PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) e.
Functional Test Acceptance _ Criteria (Cont'd)
A.
For snubbers specifically required not to displace under continuous load, the ab'lity of the snubber to withstand load without displacement shall be verified.
5.
Testing methods may be used.to measure parameters indirectly or parameters other than those specified if those results can be correlated to the specified parameters through established methods.
f.
Functional Test Failure Analysis and Additional Test Lots if any snubber selected for functional testing either fails to lock up or fails to move due to manufacture or design deficiene all snubbers of the same design subject to the same defect sha be-functionally tested.
If more than two snubbers do not meet the functional test acceptance criteria, an additional lot equal to one-half the original lot size shall be functionally tested for each failed snubber in excess of the two allowed failures.
An engineering evaluation shall be made of each failure meet the functional test acceptance criteria to determine the c h a of the failure.
The result of this analysis shall be used, if applicable, in selecting snubbers to bc tested in the subsequent lot in an effort to determine the operability of othersnubberswhichmaybesubjecttothesamefailuremode.
(Selection of snubbers for future testing may also be based on the failure analysis.) T9 sting shall continue until not more than one additional inoperable snubber is found within a subsequent required lot, or all snubbers of the original inspection group have been tested, or all suspect snubbers identified by the failure analysis have-been tested, as applicable.
The discovery of loote or missing attachment fasteners will be evaluated to determine whecher the cause may be localized or generic.
The result of the evaluation wil'. be used to select other suspect l
-snubbers fo verifying the attachment fasteners, as applicable.
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Snubbers s' all not be subjected to prior maintenance-specifically L
for the pu oose of meeting functional test requirements.
L SE000YAH - UNIT 2 3/4 7-24 Amendment No. 2 143 a
I PLANT SYSTEMS BASES 3/4.7.8_ AUX 1LIARY BUILDING GAS TREATMENT SYSTEM The OPERABILITY of the auxiliary building gas treatment system ensures that radicactive materials leaking from the ECCS equipment following a LOCA are filtered prior to reaching the environment.
The operation of this system and the resultant effect on offsite dosage calculations was assumed in the accident analyses.
ANSI N510-1975 will be used as a procedural guide for surveillance testing.
Cumulative operation of the system with the heaters on for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> over a 31 day period is sufficier.t to reduce the buildup of moisture on the adsorbers and HEPA filters.
3/4.7.9 SNUBBERS Snubbers are designed to prevent unrestrained pipe or component motion under dynamic loads as might occur during an earthquake or severe transient, while allowing normal thermal motion during startup and shutdown.
The consequence of an inoperable snubber is an increase in the probability of structural damage to piping or c.omponents as a result of a seismic or other event initiati.ig dynamic loads.
It is therefore required that all snubbers required to protect the primary coolant system or any other safety system or component be operable during reactor operation.
Because the snubber protection is required o:'y during relatively low probability events, a period of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is allowed to replace or restore the inoperable snubber (s) to operable status and perform an engineering evaluation on the supported component or declare the supported system inoperable and follow the appropriate limiting condition for operation statement for that system.
The engineering evaluation is performed to determine whether the mode of failure of the snubber ha:, adversely affected any safety-related component i
or system, Safety related snubbers are visually inspected for overall integrity and i
operability.
The inspection will include verification of proper orientation, adequate fluid level M applicable. and attachment of the snubber to its l
anchorage.
The removal of insulat.)n or the verification of torque values for threaded fasteners is not required for visual inspections, The '"cection frequency is based upon maintaining a constant level of snubber prote..on.
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 i
interval has elapsed (nominal time less 25 percent) may not be used to lengthen c
the required inspecticr; interval.
Any inspection whose results require a i
L shcrter inspection interval will override the previous schedule.
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l SEQUOYAH - UNIT 2 B 3/4 7-5
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_ PLANT SYSTEMS BASES 3/4.7.9 SNUBBERS (cont'd)
Whef, the cause of the rejection of a snubber in a visual inspection is clearly established and remedied for that snubber and for any other snubbers that may be generically susceptible and operability verified by inservice functional testing, if applicable, 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, or are similarly located or exposed to the same environmental conditions such as temperature, radiation and vibration.
Test groups may be establishedbasedondesignfeaturesandInstalledconditionswhichmaybe expected to be generic.
fach of these groups-are tested separately unless an engineering analysis indicates the group is improperly constituted.
All scapect snubbers are subject to inspection and testing regardless of test groupings.
To further increase the assurance of snu3ber reliability, functional tests shall be performed during each eefueling outage.
These tests will include stroking of the snubbers to verify proper movement, activation, and bleed or release.
The performance of hydraulic snubbers generally depends on a clean, deserated fluid contained within variable pressure chambers, flowing at closely controlled rates.
Since these characteristics are subject to change with exposure to the reactor environment, time, and other factors, their performance i
within the $pecified range should be veri'ied.
Mechanical snubbers which depend upon overcoming the inertia of a mass and the braking action of a capstan spring contained within the snubber for limiting the acceleration of the attached component (within the load rating of the snubber) are not subject to changes in performance in the saae manner as hydraulic snubbers.
Pending l
the development of information regarding the change during the service of t1e snubber of the acceleration / resistance relationship and the optimum method for detecting this change, these mechanical snubbers may be tested to verify that when subjected to a large change in velocity the resistance to movement i
increases greatly.
The performance change information was developed in l
order to establish test' methods to be used during and after the first refueling i
outage.
(
Ten percent of the total population of snubbers is an adequate sample for l
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functional tests.
The initial sample is to be proportioned among the groups in order t' obtain a representative sample.
Observed failures of more than two I
-snubbers in the initial lot will require an engineering analysis and testing of
. additional snubbers selected from snubbers likely to have the same defect.
A thorough inspection of the snubber threaded attachments to the pipe or components and the anchorage will be made in conjunction with all required
[
functional tests.
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i SEQUOYAH - UNIT 2 B 3/4 7-6 Amendment No. 2 143 i
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BASES
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3/4.7.9 SNUBBERS (cont'd)
A list of individual snubbers with detailed information of snubber location and size shall be available at the plant in accordance with Section 50.71(c) of 10 CFR Part 50.
The accessibility of each snubber shail be determined
- based upon the existing radiation levels and the expected time to perform a visual inspection in each snubber location as well as other factors associated with accessibility during plant operations (e.g., temperature, atmosphere, location etc.), and the recommendations of Regulatory Guide 8.8 and 8.10.
The addition or deletion of any hydraulic or mechanical snubber shall be made in i
accordence with Section 50.59 of 10 CFR Part 50.
3/4.7.10 SEALED SOURCE CONTAMINATION The limitations on removable contamination for sources requiring leak testing, including alpha emitters, based on 10 CFR 70.39(c) limits for plutonium.- This limitation will ensure th3t leakage from byproduct. source, and special nuclear material sources will not exceed allowable intake values.
a Sealed sources are classified into three groups according to their use, with surveillance requirements commensurate with the probability of damage to a t
i i
source in that group.
Those sources which are frequently handled are required to be tested more often than those which are not.
Sealed sources which are continuously enclosed within a shielded mechanism (i.e., sealed sources within i
radiation nionitoring or boron measuring devices) are considered to be stored and need not be tested unless they are removed from the shielded mechanism.
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f 9
i 1-0 SEQUOYAH - UNIT 2 B 3/4 7-6a Amendment No. 31, 143
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