ML20204J168
| ML20204J168 | |
| Person / Time | |
|---|---|
| Issue date: | 10/24/1984 |
| From: | Olshinski J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20204J172 | List: |
| References | |
| GL-84-13, NUDOCS 8412100332 | |
| Download: ML20204J168 (9) | |
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MEMORANDUM FOR:
Darrell G. Eisenhut, Director, Division of Licensing. Cffice of Nuclear Reactor Regulation FROM:
John A. 01shinski, Director, Division of Reactor Safety
SUBJECT:
INCONSISTENCIES IN SNUBBER TECHNICAL SPECIFICATIONS AND RECOMMENDED CHANGES A review of Technical Specifications (TSs) that specify surveillance requirements of mechanical and hydraulic snubbers for all Region II Operating License (OL) facilities was recently completed. The review was accomplished by comparing the TS for each facility with the standard snubber TS attached to Generic Letter 84-13 and the Catawba Unit 1 Proof and Review snubber TS which we understand is the most current version of the snubber TS.
Significant variations in the snubber surveillance requirements were identified.
The TSs for Hatch, Crystal River, and Brunswick were not included in this review.
An amendment to the Hatch TS is currently undergoing review in Region II.
Review of an amendment for the Brunswick TS was recently completed in Region II.
These amendments will result in standardizing the Hatch and Brunswick TSs.
To the best of our knowledge, Crystal River has not submitted an amendment for the TS as requested in the NRC November 20, 1980 letter to all power reactor licensees,
Subject:
Technical Specification Revisions for Snubber Surveillance.
Region II has discussed this potential problem with the NRR Licensing Project Manager for Crystal River who is currently reviewing this item. Therefore, the deficiencies we noted in the Crystal River snubber TS are not included in this memorandum.
The significant variations noted during the review are summarized below:
a.
The LCOs for Browns Ferry, Oconee, Robinson, and Surry do not require cubbers to be operable during refueling and cold shutdown as reouired in paragraph 3.7.9 of the Standard TS and paragraph 3.7.8 of the Catawba TS.
Ihe LCOs in the St. Lucie 1 and Surry TSs also do not require an engineering evaluation when inoperable snubbers are found.
b.
The schedule for the subsequent visual inspection period when visually inoperable snubbers are found is the same for all facilities. However, the Oconee TS permits lengthening the inspection intervals by two steps as compared to paragraph 4.7.9.a of the standard TS and the paragraph 4.7.8.b of the Catawba TS which state that the inspection interval be lengthenec only one step at a time.
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CONTACT.
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D 2.
Darrell G. Eisenhut 2
OCT 2 4 s84 c.
The Oconee and Turkey Point TSs do not require testing of all snuccers of same design or manufacturer if a functional test failure was due to a cesign or manufacturer defect which resulted in the snutter being locked up ( f ec:en in place) or falling to lock up as is required in the standard TS, paragraph 4.7.9.c. and the Catawba TS, paragraph 4.7.8.g.
d.
The St. Lucie, Sequoyah, and Summer TSs do not require retesting of snubeers in the same location as snubbers which failed the previous functional test during the next functional test period in addition to the sample selected for testing as specified in the standard TS, paragraph 4.7.9.c, and the Catawba TS, paragraph 4.7.8.e.
e.
The Browns Ferry, Sequoyah, and Summer functional test acceptance criteria for mechanic.' snubbers do not require testing to verify that activation of inesia dependent mechanical snubber is achieved within the specified range in both tension and compression.
This is specified in the Standard TS, paragraph 4.7.9.e and the Catawba TS, paragraph 4.7.8.f.
f.
The service life programs required by the Browns Ferry, McGuire, Oconee, Robinson, St. Lucie, Sequoyah and Summer TSs do not comply with the require-ments specified in the Standard TS, paragraph 4.7.9.f, and the Catawba TS, paragraph 4.7.8.1.
These specifications address only the service life of hydraulic snubber seals and not an indepth service life program for all l
snubbers, mechanical and hydraulic, and all critical snubber components.
We request that NRR take action to eliminate the variations stated above from the listed TS.
It is our goal to use a uniform approach to inspect snubber surveillance activities at all Region 11 facilities.
Since all snubbers are similar, in some cases exactly the same, at all facilities, there should not be any variation in surveillance testing requirements and testing acceptance criteria between facilities.
We would also like to take this opportunity to offer the following comments on the current standard TS for snubber surveillance:
i i
4.
Paragraph 4.7.8.a of the Catawba TS defines snubber type as snubbers of the same design and manufacturer.
This definition is too broad. We recommend that type be defined as snubbers of the same general design, either mechanical or hydraulic, and delete the words "and manuf acturer." We feel i
that many utilities will classify snubbers of dif ferent manufacturers as different types of snubbers, where, in fact, the snubbers are all. the same i
type.
For example, Bergen-Patterson (B&P) hydraulic snubbers will be classified as one type, Grinnell hydraulic another, and so on.
They are, for all practical purposes, the same type snubber utilizing the same 2
operating principles and similar components.
i b.
Inclusion of words "oa any system" in TS 4.7.8.b assumes that visual defects j
noted during visual inspections are dependent on the system on which they l
are installed.
This is not necessarily the case.
The standard TS
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(enclosure to May 3,1984 Generic Letter) permits the licensee to reach this conclusion af ter performing an engineering study in which the licensee is t
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required to demonstrate and doc. ment that tre visual ce'ect is unicoe and limited to a particular system as a result of seme event, sucn as a transient.
In the Catawba TS, the assumption is made that the visaal ce'ect is system oriented and does not require the licensee to per#orm any evaluation.
i i
In paragraph 4.7.8.b, the table governing the frecuency of subsequent visual c.
inspections is based on the number of inoperable snubbers found in tne inspection period.
This table is the same for all Region II sites, regardless of whether the plant has 30 snubbers or 1200 snuobers.
This table should be revised to substitute a percentage of inoperable snubcers for the number of inoperable snubbers.
If two visually inoperable snubbers are found at Robinson, which has 30 snubbers, the subsequent reinspection interval is six months.
If two inoperable snubbers are found at Summer, which has 1100 snubbers, the subsequent reinspection interval is also six months.
We believe this criteria is too restrictive for Summer and not strict enough for Robinson. Therefore, we believe the reinspection interval should be based on percentage of inoperable snubbers.
d.
Paragraph 4.7.8.d. line 5, requires inspection of systems "within six months following such an event." This appears to be contrary to requirement of Criterion XVI of 10 CFR 50, Appendix B, which requires prompt identification and correction of malfunctions, deficiencies, etc. Operational data should i
be reviewed daily or weekly, and if a problem is suspected, visual inspection should be scheduled and performed as soon as possible.
There is j
no reason to wait six months.
e.
Paragraph 4.7.8.e.,
discusses functional tests.
In sample plan 2, the 3
results of functional testing are plotted at the "end of each' days testing."
The relationship between test results and the end of the each days testing is not clear.
The curve, Figure 4.7-1, appears to be a continuous function i
based on a statistical calculation of a confidence interval.
In this regard, it appears that a snubber should be plotted as tested and action l
taken according to the requirements of the curve and location of the plotted point. We note that in sample plan 3, each snubber point must be plotted on the curve as soon as the snubber is tested. We feel that the phrase "end of each days testing" should be deleted from the TS.
The curve should be used to determine action.
We request that the above comments be considered and that appropriate revisions to the snubber TS be made. We have included as an enclosure to this memo a recommended generic TS for snubbers which incorporates the above comments.
Please contact us if additional information is needed regarding our concerns.
John A. Olshtnsai A
\\
Enclosure:
(See page 4)
Darrell G. Eisenhut 4
g
Enclosure:
Region II Recommended Generic TS for Snubbers cc w/ enc 1:
T. Martin, RI L. Spessard, RIII R. Denise, RIV T. Bishop, RV R. Kiessel, IE 1
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ENCLCSURE REGION II RECCMMENDED GENERIC TS FOR SNUEBERS PLANT SYSTEMS
$ NUB 8ERS LIMITING CON 0! TION FOR OPERATION 3.7.5 All hydraulic and mechanical snubbers shall be OPERABLE.
APPLICABILITY:
For BWRs OPERATIONAL CONDITIONS 1,
2, and 3.
OPERATICNAL CONDITIONS f and 5 for snubbers located on systems required OPERABLE in those OPERATIONAL CONDITIONS.
OR APPLICABILITY:
For PWRs MODES 1, 2, 3 and 4.
(MODES 5 and 6 for snubbers located on 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 f.he inoperable snubber (s) to OPERABLE status and perform an engineering evaluation per Specification 4.7.5.g on the attached component or declare the attached system inoperable and follow the appropriate ACTION statement for that system.
SURVEILLANCE REQUIREMENTS 4.7.5 Each snubber shall be demonstrated OPERABLE by performance of the followtiit augmented inservice inspection program and the requirements of Specification 4.0.5.
4.
Inspection Types As used in this specification, type of snubber shall mean snuebers of the same design, e.g.,
hydraulle snubber, or mechanical snubber irrespective of capacity.
b.
Visual Inspections
$nubbers are cettgorized as inaccessible or accessible during reactor operation.
Each of these groups (inaccesstble and accessible) may be inspected independently according to the sc*edule below.
The first inservice visual inspection of each types of snubber shal' De performet after 4 months but within 10 months of commencing PC'nER OPERA!:0N and shall include all hydraulic and mechanical snubbers.
If all snutbees of each type are found OPERABLE during tae 'trst $nse vice visual
)
Enclosure 2
inspection, the second inservice visual inspection shall be performed at the first refueling outage.
Otherwise, subseqt ent visual inspections shall be performed in accordance with the following schedule:
Percentage of Inoperable Snubbers of Each Type Subsequent Visual Per Inspection Period Inspection Period *#
(TO BE DETERMINED) 18 months 25*i 12 months 25%
6 months 2 25%
124 days 2 25%
62 days 25%
I 31 days t 25%
c.
Visual Inspection Acceptance Criteria Visual inspections shall verify that:
(1) there are no visible
(
indications of damage or impaired OPERASILITY, (2) attachments to the j
foundation or support structure are secure, and (3) fasteners for attachment of the snubber to the component and to the snubber anchorage
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are secure.
Snubbers which appear inoperable as a result of visual inspections may be determined OPERABLE for the purpose of establishing the next visual inspection interval, provided 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 in the as-found condition and determined OPERA 8LE per Specifications 4.7.5.f.
All l
snubbers connected to an inoperable common hydraulic fluid reservoir j
shall be counted as inoperable snubbers.
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d.
Transient Event Inspection l
An inspection shall be performed of all hydraulic and mechanical snubbers attached to sections of systems that have experienced unexpected, potentially damaging transients as determined from a review of operational data and a visual inspection of the systems.
In addition to satisfying the visual inspection criteria, freedom-of-i motion of mechanical snubbers shall be verified using at least one of l
the following:
(1) manually induced snubber movement; or (2) evalua-tion of in place snubber piston settings; or (3) stroking the mechanical snubber through its full range of travel.
I j
- The inspection interval shall not be lengthened more than one step at a time I
unless a generic problem has been identifled and corrected; in that event the j
f aspection interval may be lengthened one step the first time and two steps thereafter if ne Inoperable snubbers are found.
- The provisions of Specification 4.0.2 are not applicable.
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Enclosure 3
e.
Functional Test During the first refueling shutdown and at least once ::e r 's ent*s thereafter during shutdown, a representative sample of snuteers small be tested using one of the following sample plans.
The sample plan shall be selected prior to the test period and cannot ce c* an';ed during the test period.
The NRC Regional Administrator shall be notified in writing of the sample selected prior to the test period or the sample plan used in the prior test period shall be implemented:
1.
At least 10% of the total of each of snubber shall De functionally tested either in place or in a bench test.
For each snubber of a type that does not meet the functional test acceptance criteria of Specification 4.7.5.f, an additional 10*. of that type of snubber shall be functionally tested until no more failures are found or untti all snubbers of the type have been functionally tested; or 2.
A representative sample of each type of snubber shall be functionally tested in accordance with Figure 4.7.5-1.
"C" is the total number of snubbers of a type found not meeting the acceptance requirements of Specification 4.7.5.f.
The cumulative number of snubbers of a type tested is denoted by "N",
After testing N snubber, the values N&C shall be plotted on Figure 4.7.5-1.
If the point plotted f alls in the " Reject" region 'all snubbers of that type shall be functionally tested.
If the point plotted falls in the " Accept" region, testing of snubbers of that type may be terminated.
When the point plotted lies in the
" Continue Testing" region, x (specify number) additional snubbers of that type shall be tested until the point falls in the " Accept" region or the " Reject" region, or all the snubbers of that type have been tested.
3.
An initial representative sample of 55 snubbers shall be functionally tested.
For each snubber type which does not meet the functional test acceptance criteria, another sample of at least one-half tne size of the initial sample shall be tested until the total number tested is equal in the initial samole size multiplied by the f actor, 1 + C/2, where "C" i s the number of snubbers found which do not meet the functional test acceptance criteria.
The results from this sample plan shall be plotted using an " Accept" line which follows the equation N = 55(1 + C/2).
Each snubber point should be plotted as soon as the snubber is tested.
If the point plotted falls above the " Accept" Itne, testing must continue until the point falls in the " Accept" region or all the snubbers of that type have been tested.
The representative sample selected for the functional test sample plans shall be randomly selected from the snubbers of each type and reviewed before beginning the testing.
The review shall ensure as far as practical that they are representative of the various conf twrat'ons, operattng environments, range of,tze, and capacity of snute,-s of eacn c
l Enclosure 4
type.
The representative sample, shall r:'.
to tre m tent ;:r ict :a : 'y,
include those snubbers tested in a previous r.-asentati ve samole.
'n e
addition to the representative sample, snutters d'en fat'ed tae previous functional test shall be retested daring the nest tast ::er:cc.
If a spare snubber has been installed in place of a failed snucbar, then both the failed snubber (if it is repaired and installec in another position) and the spare snubber snall be retested.
Test results of these snubbers may not be included for the re-sampling.
I' during the functional testing, additional sampiing is recuired due to failure of only one type of snubber, the functional testing results shall be reviewed at the time to determine if additional samples should be limited to the type of snubber which has failed the functional
- testing, f.
Fy ctional Test Acceptance Criteria The snubber functional test shall verify that:
1.
Activation (restraining action) is achieved within the specified range in both tension and compression; 2.
Snubber bleed, or release rate where required, is present in both tension and compression, within the specified range, 3.
Where required, the force required to initiate or maintain motion of the snubber is within the specified range in both directions Of travel; and 4.
For snubbers specifically required not to displace under continuous load, the abili'.y of the snubber to withstand load without displacement.
g.
Functional Test Failure Analysis An engineering evaluation shall be made of each failure to meet the functional test acceptance criteria to determine the cause of the failure.
The results of this evaluation shall be used, if applicable, in selecting snubbers to be tested in an effort to determine tne OPERABILITY of other snubbers irrespective of type which may be subject to the same failure mode.
For the snubbers found inoperable, an engineering evaluation snall be performed on the components to which the operabl.* snubbers are attached.
The purpose of this engineering evaluation shall be to determine if the components to which the inoperable snubbers are attached were adveesely affected by the operability of the snubbers in order to ensure that the component remains capable o' -aeting the designed service.
e ir o
Enctosure 5
If any snubber selected f0r functional testing eithee fatis to lack up or fails to move, i.e.,
frozen-in place, the cause will ce evaluated and if caused by manufacturer or design deficiency all scubbers of tre same type subject to the same defect shall De functionally tested.
This testing requirement shall be independent of the requirements stated in Specification 4.7.5.e for snubbers not meeting the functional test acceptance criteria.
h.
Functional Testing of Repaired and Replaced Snubber-snubbers which fail the visual inspection or the functional test acceptance criteria shall be repaired or replaced.
Replacement snubbers and snubbers which have repairs which might affect the functional test result shall be tested to meet the functional test criteria before installation in the unit.
Mcchanicai snubbers shall have met the acceptance criteria subsequent to their most recent service, and the freedom-of-motion test must have been performed within 12 months before being installed in the unit.
1.
Snubber Service Life Monitoring program The service life of hydraulic and mechanical snubbers shall be monitored to ensure that the service life is not exceeded between surveillance inspections.
The maximum expected service life for various seals, springs, and other critical parts shall be determined and established based on engineering information and shall be extended or shortened based on monitored test results and failure history.
Critical parts shall be replaced 50 that the maximum service life will not be exceeded during a period when the snubber is required to be OPERABLE.
The parts replacements shall be documented and the documentation shall be retained in accordance with Specification 6.10.2.
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