ML20031D252
| ML20031D252 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/06/1981 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20031D255 | List: |
| References | |
| A01638, A1638, NUDOCS 8110130184 | |
| Download: ML20031D252 (5) | |
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October 6, 1981 4
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1 Docket No. 50-245 O
4 A01638 U 58.Jm 1;9 OCT131981>[8 osan== N 8l coam s
Director of Nuclear Reactor Regulation
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Attn:
Mr. Dennis M. Crutchfield, Chief g\\
Operating Reactors Branch #5 j *.
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U. S. Nuclear Regulatory Commission Washington, D.C. 20555
References:
(1)
D. G. Eisenhut letter to All SEP Licensees, dated March 23, 1981.
(2)
W. G. Cour.sil letter to D. M. Crutchfield, dated August 11, 1981.
Gentlemen Millstone Nuclear Power Station, Unit No. I Technical Specifications for Snubber Surveillance t
In Reference (1), the NRC Staff recuested that Northeast Nuclear Energy Company (NNECO) propose Technical Specifications for the inservice surveillance of snubbers at Millstone Unit No. 1.
NNECO informed the Staff in Reference (2) that the requested license amendment application would be docketed on or about September 15, 1981. Ac.:ordingly, pur-suant to 10CFR50.90, NNECO hereby proposes to amend its operating license, DPR-21, by incorporating the following revisions into the Millstone Unit No. 1 Technical Specifications:
l Revise Sections 3.6.I and 4.6.I, Snubbers, as shown in the attachment.
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. The proposed changes incorporate modified Standard Technical Specification pages for snubbers, as provided in Reference (1), into the Millstone Unit No. 1 Technical Specifications. The Reference (1) model Technical Spec-ification pages have been modified to accommodate plant specific con-ditions as well as the Millstone Unit No.1 Technical Specification format.
Justification for the deviations are discussed below. As requested by Reference (1), NNECO has included a new Table 3.6.1.b which lists the safety related mechanical snubbers in use at Millstone Unit No. 1.
NNECO l
has included in proposed Tables 3.6.1.a, additional flydraulic Snubbera, installed on the Isolation Condenser during the last refueling outage.
The snubber visual inspection schedule is included in Specification 4.6.I.1 of the Millstone Unit No.1 Technical Specifications. As the Plant has been in commercial operation for over ten years, the wording requiring visual inspections after four (4) months but within ten (10) months from commencement of power operation has been deleted.
For the purposes of visual inspections, NNECO proposes to divide the snubbers at Millstone Unit No. 1 into two groups: mechanical and hydraulic.
Each group is further subdivided into accessible and in-accessible subgroups. The grouping by snubber type and accessibility meets the intent of the model Technical Specifications and provides for addit;)nal clarification for the required visual surveillances.
Since the visual inspection criteria are different for mechanical and hydraulic snubbers, the two snubber types must be treated separately for the purposes of visual inspections.
The visual inspection acceptance criterion in Model Specification 4.7.9.b has been modified as described in the proposed Specification 4.6.I.2 to clarify the intent of the visual inspections. Proposed Specification 4.6.I.2 reflects two (2) distinct categories for visual acceptance of a snubber (1) snubbers which exhibit visual indications of impaired OPERABILITY, and (2) snubber locations which exhibit visual indications of detachment from foundations or supporting structures which in no way effect actual snubber operability. NNECO has not in-cluded a requirement to manually induce movement of a snubber without disconnecting the snubber. The results of such " twist" tests were determined to be invalid and without merit during the recent snubber inspections mandated by I&E Bulletin No. 81-01.
NNECO has not proposed to include words within the Technical Specifications visual inspection critorion that contain an inordinate amount of detail which is more appropriately provided for in surveillance procedures.
Specifically, the verbage referring to the failure of a hydraulic snubbcr due to the lack of a cover on the fluid port was deleted. This level of detail is more appropriately contained in surveillance procedures.
It is noted that current procedures require that hydraulic snubbers whose fluid port is not covered be declared inoperable.
. Snubber functional testing will be performed on a representative sample consisting of 10% of each type of snubber, mechanical or hydraulic, in use at Millstone Unit No.1.
The statistical sampling criterion defined in the nodel Technical Specifications has been deleted.
711s criterion is applicable to a total snubber population of greater than or equal to five hundred (h 500). As Millstone Unit No. 1 utilizes much fewer than 500 snubbers, this Specification does not apply and the representative sample defined as 10% of each type of snubber (mechanical or hydraulic) is adequate.
The requirement to choose at least 25% of the snubbers in the representative sample from the three categories listed in Section 4.7.9.c of the model Specifications has been deleted. Based on the results of inspections and analytical efforts required to respond to I&E Bulletin No. 81-01, NNECO has determined that the snubbers included in the three categories listed in model Specification 4.7.9.c do not necessarily represent those snubbers which are the most crucial to safety or more susceptible to damage or impaired operability. To determine the relative importance of each snubber or the susceptability of failure of a snubber in a particular location would require a detailed, case by case analysis assuming a variety of failure modes. This is clearly not the intent of the Specifications and would otherwise negate the concept of a random sample. The deletion of this requirement is judged not to compromise the safety of the plant.
Snubbers have not been categorized into various groups by operating environments. This task would be extremely dif ficult, if not impossible, to accomplish particularly in inaccessible areas of the Plant. The enhanced surveillance requirements incorporating a representative sample of snubbers in use at the Plant ensures an increased inspection frequency for all snubbers than has previously been realized.
In addition, NNECO has incorporated in proposed Specification 4.6.I.3 the requirement to retest those snubbers in locations where snubbers had previously failed functional tests due to environmental or operational conditions. This will ensure that snubbers installed in potentially adverse locations will be surveilled more frequently.
Inoperable snubbers repaired and returned to service will be functionally tested on a random basis. Additional surveillance frequencies are not required since any repaired snubber is rebuilt and tested prior to reinstallation in the Plant. Vendor certification as to the acceptability of the snubber for continued operation accompanies any rebuilt snubber. NNECO considers a rebuilt snubber equivalent to a new urit and surveillance over and above the required random sampling is excessively' conservative.
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NNECO has modified model Technical Specification Section 4.7.9.d.2, r
Hydraulic Snubbers Functional Test Acceptance Criteria, to reflect actual cnubber operation. Snubbers specifically required not to displace under continuous load are not utilized, nor are they planned for future use at Millstone Unit No. 1.
NNECO intends to verify that the mechanical snubbers listed in Table 3.6.1.b have freedom of movement over their full range of compression and tension. Specification 3.6.I.4.b has been modified accordingly.
Additional functional testing of mechanical snubbers will be performed upon the availability of testing equipment on-site. As such, model Specifications 4.7.9.e does not apply.
Model Technical Specification 4.7.9.f is not proposed. This requirement is fulfilled by current Technical Specification 6.10.2.h which requires the maintenance of records of inservice inspections performed pursuant to Technical Specifications.
The Reference (1) model Technical Specification Bases have also been modified slightly to support the proposed Technical Specification 3.6.I and 4.6.I, Snubbers.
The proposed Technical Specifications included in Attachment 1 incor-porate all applicable positions of the model Technical Specifications provided in Reference (1).
Modifications to the Reference (1) model Specifications were necessitated to enhance the overall clarity of the proposed Technical Specifications; however, the original intent of the Staf f has not been altered. NNECO has determined that the proposed Technical Specifications for snubber surveillance provide an assurance of safety equivalent to that of the Reference (1) model. The overall intent of the Staff to provide increased surveillance requirements for snubbers, particularly the addition of the safety-related mechanical snubbers, and to upgrade inspection techniques has been accomplished by the attached proposed Technical Specification.
The above proposed changes have been reviewed pursuant to 10CFR50.59 and have not been found to constitute an unreviewed safety question.
1 The Millstone Unit No. 1 Nuclear Review Board has reviewed and approved the above proposed changes, and has concurred in the above determination.
NNECO has reviewed the above proposed license amendment pursuant to the requiremen;s of 10CFR170, and has determined that the proposal con-stitutes a Class 3 mnendment. The basis for this determination is that the proposal involves a single safety issue which does not involve a significant hazards consideration.
Therefore, enclosed herewith is the appropriate Class 3 license amendment fee of four thousand ($4000) dollars.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY M
W. G. Counsil Senior Vice President
i STATE OF C0hWECTICUT )
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- i COUNTY OF HARTFORD a
Then personally appeared befor:s me W. G. Counsil, who being duly sworn, did state that he is Senior Vice President of Northeast Nuclear Energy Compar/, a Licensee herein, that he is authorized to execute and file j
the foregoing information in the name and on behalf of the Licensees herein and that the statements contained in said information are true and correct to the best of his knowledge and belief.
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e Notary Public '
t.iy Commission Expires brch 31, 1936 I
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