ML18025B783
| ML18025B783 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/24/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18025B782 | List: |
| References | |
| NUDOCS 8206040067 | |
| Download: ML18025B783 (4) | |
Text
WASHINGTON, D. C. 20555 SUPPORTING AMENDMENT No. 84 To FACILITY OPERATING LICENSE NO.
DPR-33 AMENDMENT NO. 81 TO FACILITY OPERATING LICENSE NO. DPR-52 AMENDMENT NO. 55 TO FACILITY OPERATING LICENSE NO.
DPR-'68 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT, UNITS: 1",
2 AND 3~..
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DOCKET NOS. 50-259 50-260'AND 50-296 gp,R REC(lc Wp
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION Author:
Richard J. Clark 1.0 2.0 3.0 Introduction By letter dated April 28, 1981 (TVA O'FNP TS,158) and supplemented by letter dated March 9, 1982, the Tennessee Valley Authority (.the.licensee or TVA} requested amendments to Factl ity Operating License Nos
. DPR-33, DPR-52 and DPR-68 for the Erowns Ferry Nuclear Plant, Uni'ts 1, 2 and 3.
The proposed amendments would revise tlie Techntcal Specifications appended to the above Facili'ty Operating Ltcenses to add additional requirements for inspectton of snuGKers and seismic restrai,nts in response to our generic request of November 20, 1981 to All Power Reactor Licensees.
Back round To reflect accumulated expertence obtained from operating plants in the past. several
- years, NRC issued Revi'sion 1 of the Standard Teclinical Specificati'ons on the surveillance requirements for safety-related snubbers.
On November 20, 1930, tlits document was transmitted to operating plants excluding those under the Systematic Evaluatton Program (SEP} along witII. a request for sufi'ttal of appropriate license amendments to incorporate tlie requirements of thts revision within 120"days The same request was extended to SEP plants on March '23, 1981.
Descr i'ion 'and Discuss ion Numerous. di'scoveries of i',noperative, snuMers in th peiiod of 1973 to 1975 resulted in their surveillance requirements in the Technica,l Specifications for operating reactor plants.
However, several defictencies were identified after the original requirements were in force'for several years.
These deficiencies are.:
820b0400b7 820524 PDR ADOCK 05000259 P
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2 1.
Mechanical snubbers were not included in these requirements.
\\
2.
The rated capacity of snuMeis was used as a, li'mit to the inservice test requtrement.
3.
NRC approval was necessary for the acceptance of seal materials.
4.
Inservice test requirements were, not clearly defined.
5.
In-place inservlce testtng was not permttted, Since mechanical snuMers were not sub)ect'o any suryei,'ll~nce require-
- ments, some licensees and permi'.t fielders. Believed.that meccan'i'.cal snub5ers were preferred Ey NRC.
Hany plants used'meclikni'cal snuE5er i aa optginal equipment and many otKera requested'to replace"tKei.i. Kydraultc snuKers wit% mechanical ones to simplify or avoid an ixservice'urveillance'rogram.
Tliis is directly contradtctory to NRC's intenti'on, wliere for an unsurveyed mechanical
- snuEFer, the most likely failure is permanent lock-up.
This failure mode can Ke Barmful to tfie system during normal plant operations.
During the period of 1973-1975, when the first.hydraultc znuMer surveillance requirements tn the Teclintcal Speciftcattons were drafted, a c'ompromise was made to limit the testing of snuMers'o 'those with.,
rated capacity of not more. than 5Q,OOQ 16s.,
Thi's'as-because of the'vailable c'apacity of the test equi'pment and'he.requtrement to test some parameters at tLe snubber rated load, Since'tfien,.-'greater.
equipment capacity and better understandi'ng of parametric corr elati'on both developed, To maintain this ar5itrary 56,000. 15.. limit could mean an unnecessary compromise on plant safety.
The ortginal hydraulic. snu55ev problem star ted from leaking seals.
Host seal materials of the 1973 vintage could not withstand the temperature, and irradiation environments.
Ethylene propylene was the first material that could offer a reasonable service life for those seals.
In order to discourage the use of unproven material for those seals, the words "NRC approved material" were used in the Technical Specifications.
Staff members were asked to, approve different seal materials on many occasions.
Consequently, si.nce the 5asi's for tKe approval was not deftried, the development of better seal materials 5y the industry was actually di'scouraged.
The not-well-defi'ned acceptance'cr i'teria tn the earlier versi,on of tlie testing.requirem'ents resulted in non-uniform interpretations and implementation.
Acceptance Cr iteria were set individually at widely different ranges.
Since tAe rationale of adopting a specific acceptance criteria was not clear, I&E inspectors found it imposst51e ta make any necessary corrections.
In some cases, snubhers were tested without reference to acceptance cri'teria,'
4.0
. Testing of snubbers was usually. accomplished by removing snubbers'rom their installed positions, mounting them on a testing rtg, conducting the test, removtng tliem from r tg, and retnstalling them to the working position.
Many snuB6ers were damaged tn the removing and retnstallation process.
This defeated the purpose for conducting tests.
Since methods and equipment Fiave Keen developed to conduct,.tn-place tests on snu66ers, taking advantage of these developments could result tn mtnimizing the
..damage to snuBBers caused By removal and reinstallation plus time and cost savings to the plants.
1 From tKese Qgpt-cori',ngz tt ~s: concluded'that tbe snuBKep surveillance'equirements for the Technical Spectftcattons should Ke revised, Evaluation In response to our generic request, TVA initially proposed changes to the snubber surveillance requirements for Browns ferry Uni'ts 1, 2 and 3 By letter dated April 28, 1981.
Eased on our r eview, we determined that with a few minor exceptions, TVA had adopted the requirements in the proposed standard Technical Specifications transmitted by our request of November 20, 1980..
One of the devtations proposed by TYA was that, if there was no vlsi5le i'ndtcatton of tnoperability in a lot of,snubbers
'or two successi've
'18 month. periods,'hat the visual inspection lot be reduced from 100'A to 50%.
A similar proposal was made by several other licensees In our letter of November'18,: 1.981'o TVA, we agreed that the,.development of improved snu65er
- designs, the'use of seal mater tais tn hydraultc snu66er s that are more resistant to temperature and trradtatton environ-
- ments, more stringent quality assurance and testing and other factors had significantly reduced the pro5lems discussed tn Section 3.0 a6ove.
- However, we advised TVA and the other licensees that there was not, as
- yet, a sufficient operating history and data base to confirm the indicated increase in expected service life-.
Accordingly, we requested TYA to revise the proposed Technical Specifications to. provide for 100Ã visual inspection of all snu56ers each fuel cycle.
TVA's submittal of March 9, 1982 revised the Technical Specifications, as;-requested in our letter of Novemher 18, 1981, while su5mttttng additional justification for TVA's initial proposition for reduced visual inspection 6ased on at least three years performance without indication of deficiencies.
Although the staff is evaluating the snubber performance
- data, a staff position on reduced frequency of surveillance has not been developed.
Me have reviewed the revised Technical Specifications submitted by TYA's letter of March 9:, 1982 and have determined that they incorporate the requirements stated in our letter-'- of November 20, 1986.
The new surveillance requirements will.correct the deficiencies discussed tn Section 3.Q aBove in the following manner:
1.
Mechanical snu5bers are now. included tn the surveillance program.
2.
No ar5ttrary snuMer capactty ts used as a limit to the tnservtce test requi'rements.
3.'eal mater tal no longer't equhes.'NRC approval.
A-monttor tng program will be implemented to assure that, snubbers are functiontng within
'heir ser vtce 1 tfe, 4.
Clearly deftned inservtce test requirements for snu65era wtll he impl emented.
5.
Rn-place tnsePYl,ce tektlng sQ,ll Ee. permttted; Ve conclude that the tecFintcal spectftcattons su5r0ttted + Tyg tnclude the necessary requirements for survetllance'f safety-related
- snuKers, as defined in our letter of November 20, 1980 and are therefore acceptable.
5.0 Environmental Considerations Me have determined that the amendments do not authorize a change tn
'ffluent types or total amounts nor an tncrease tn power level and-wtll not result in any stgntftcant environmental impact',
Havtng made 'this
. determination, we have further concluded that the amendments tnvolve an action which is insignificant from the standpoint of environmental impact and pursuant to 10 CFR 51.5(d)(4) that an environmental impact statement or negative declaration and environmental impact'appraisal need not be prepared in connection with the issuance of the. amendments.
6.0 Conclusion Me have concluded, based on the considerations dtscussed above, that; (1) because the amendments-do not involve a significant increase in the probability or consequences of accidents previously constder ed and do not involve a significant decrease tn a safety margin, the amendments
'o not involve a significant hazards consideration, 9) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed
- manner, and (3) such activities will be conducted in compliance with the Commission's regulations, and',the issuance of these amendments will not Ge inimical to the common defense and security or to the health and safety of the public.
Dated:
May 24, 1982