ML20003E149
| ML20003E149 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck, Millstone File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 02/19/1981 |
| From: | Counsil W, Fee W NORTHEAST UTILITIES |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| A01531, A1531, IEB-81-01, IEB-81-1, TAC-08952, TAC-8952, NUDOCS 8104020338 | |
| Download: ML20003E149 (5) | |
Text
F NORTHEAST UTHJTIES w en %n c, w,.in xv*
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dB February 19, 1981
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Docket Nos. 50-.213
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50-245 50-336 A01 91 s
Mr. Boyce E. Grier, Director Region I Office of Inspection and Enforcement U. S. Nuclear Regulatory Consission 631 Park Avenue King of Prussia, PA 19'06 4
References:
(1)
B. H. Grier letter to W. G. Counsil, dated January 27, 1981, transmitting I&E Eulletin No. 81-01.
(2)
D. G. Eisenhut letter to All Power Reactor Licensees (except SEP licensees), dated November 20, 1980.
Gentlemen:
Ha.idam Neck Plant Millstone Nuclear Power Station, Unit Nos.1 and 2
'I&E Bulletin ~No. '81-41, Mechanical Snubbers In Reference (1), the' NRC Staff provided the Connecticut Yankee Atomic Power Company (CYAPCO) and Northeast Nucle:tr Energy Company (NNECO) with a des-cription of failures of mechanical snubbers supplied by International Nuclear Safeguards Corporation (INC) and Pacific Scientific Company. As described in Reference (1), the failures are caused by oxidation of the snubber internals resulting in a frozen condition preventing normal operation. Reference (1) requested that CYAPCO and NNECO take certain actions to determine the condition of the mechanical snubbers, specifically those manufactured by INC, at the Haddam Neck Plant and Millstone Unit Nos.1 and 2.
In addition to. Reference (1), tne NRC Staff had previously requested NNECO to-propose Technical Specifications for the inservice inspection of mechanical snubbers at Millstone Unit No. 2.. This request was forwarded to NNECO in Reference (2) and was indicated to be not applicable to the SEP plants. The' model Technical Specifications included in Reference (2) in-clude provisions for visual and manual testing very nearly. identical to that of the Reference (1) Bulletin.
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c> CYAPCO and ImECO intend to utilize certain aspects of the visual and manual inspections described in Reference (2) to respond to tLe requirements of Reference (1). The approach which CYAPCO and NNECO are pursuing to fully and adequately respond to the Reference (1) requests is diacussed below:
1.
The visual inspections of the INC mechanical snubbers as well as mechanical snubbers manufactured by other vendors required by Item la, 2a, and 3b of Reference (1) vill be conducted. In addition, the visual examinations will verify the following:
that there are no visible indications of damage or impaired operability attachments to the foundation or supporting structure are secure
- 2.. Manual inspection to verify snubber freedom of moveent required by Items la, 2a, and 3b vill be conducted. NNECO and CYAPCO have deter-mined that the intent of the manual test required by the Bulletin can be satisfied through the performance of a " twist" test.
A twist test is accomplished by rotating the variable length strut of the snubber unit through a small angle with respect to the snubber unit (see attached figure). Successful completion of such a twisting notion demonstrates that the snubber internals are not frozen and are free to move as designed.
Performance of the twist test does.not require removal of the snubber from the system, and, therefore, no Technical Specification Action Statements are invoked.
By avoiding Technical Specification Action Statements as well as performing the testing on anubbers in-situ,
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expeditious completion of the manual testing required by Reference (1) is facilitated.
Based on our engineering evaluations and discussions with Staff members from both the NRC Office of Nuclear Reactor Regulations and Inspection and Enforcement, CYAPCO and NNECO conclude that the twist 1 test satisfies the intent of the manual testing required by Reference (1).
In the event movement cannot :be induced in a mechanical snubber with a twist test, CYAPCO and NNECO intend to perform a stroke test in place for that particular snubber to ensure operability.
.3.
CIAPCO and NNECO have determined that it will not be possible to comply with the operability testing requirements of Item lb of Reference (1)
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for the accessible INC mechanical snubbers at the Haddam Neck Plant and Millstone Unit No. 2.
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o The operability testing required by Item lb of Reference (1) requires removal of the snubbers from the system and sending them offwite for testing.
It is estimated that this process would take approximately three to four weeks to complete.
As the Haddam Neck Plant and Millstone Unit No. 2 are currently in Mode 1, the operability testing on the accessible snubbers cannot be completed within the constraints of Technical Specification Action Statements. As such, CTAPCO and NNECO only intend to perform op-erability tests on those INC mechanical snubbers currently in storage at the Hadde Neck Plant and Millstone Unit No. 2, at this time.
Operability testing of the required representative sanple of the accessible INC rechanical snubbers will be performed during the first outage of greance than thirty (30) days duration, and no late.- than the next refueling outage.
Operability testing of a representative cample of inaccessible INC mechanical snubbers will be completed prior to start-up from the next scheduled refueling outage for both the Haddam Neck Plant and Millstone Unit No. 2 unless inspections of inaccessible snubbers are dictated as a result of the acceulble snubber inspections.
In sumary, the following actions vill be undertaken by CYAPCO and NNECO to respond to I&E Bulletin No. 81-01 for the Eaddam Neck Plant and Millstone Unit Nos. 1 and 2 :
Haddam Neck Plant - Millstone Unit No. 2 Item la A visual and manual inspection program will be performed as described above within thirty days of the date of issuance of Reference (1).
Item lb Operability testing will be performed on all INC mechanical snubbers in storage.
Operability testing on a representative sample of accessible INC mechanical snubbers vill be completed during the first outage of greater than thirty (30) days duration. Operability tests on the snubbers in storage vill not be com-pleted within the time constraints of Item 1 of Reference (1).
NNECO vill provide the results of the operability tests on the snubbers in storage when they beco=e available.
Item 2a A visual and manual inspection program vill be conducted on all inaccessible INC mechanical snubbers during an outage of greater than thirty (30) days duration.
le-Itea 2b Operability testing of a representative sample of inaccessible INC mechanical snubbers vill be completed prior to start-up from the next scheduled refueling outage.
Iters 3 1
Visual and manual inspections, as described above, of mechanical snulebers produced by other manufacturers will be completed prior to start-up from the next refueling outage for the Haddam Necit Plant. Future inspections of all snubbers at Millstone Unit No. 2 vill be conducted in accordance with the Technical Specifications to be proposed in fulfillment of the Reference (2) request.
Millstone Unit No.1 The following actions will be completed at Millstone Unit No.1 prior to start-up from the current refueling outage.
j Item la, 2a, 3b A visual inspection and manual stroke test in place of all mechanical snubbers except those which have been examined and tested pursuant to Items 1c, 2c, and 3c of Reference (1).
Item lb. 2b Operability testing, as described in Reference (1), of a representative sample of INC mechanical snubbers from both accessible and inaccessible locations.
CYAPCO and NNECO have determined that the approach outlined above is prudent and responsive to the requirements of I&E Eulletin No. 81-01. We respect-fully request concurrance with the program described herein, such that i
the effort to respond can begin and proceed expeditiously.
t Our Staff remains available to discuss any of the aspects of the mechanical snubber inspection program described herein.
Very truly yours, CONNECTIt'JT YANKEE ATOMIC POWER COMPANY lr0R1% 9ST NUCLEAR ENERGY COMAPHY W. G. Founsil Senior Vice President Sy:
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.W. F. Fee
- Executive Vice President
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