ML19210F009
| ML19210F009 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 11/08/1979 |
| From: | Counsil W NORTHEAST UTILITIES |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-79-14, NUDOCS 7912130383 | |
| Download: ML19210F009 (9) | |
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a :=:=:1"#3"'t:l November 8, 1979 Docket No. 50-245 Mr. Boyce H. Grier, Director Region I Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
References:
(1)
W. G. Counsil letter to B. H. Grier dated August 1, 1979.
(2)
W. G. Counsil letter to B. H. Grier dated August 31, 1979.
(3)
W. G. Counsil letter to B. H. Grier dated September 28, 1979.
Gentlemen:
Millstone Nuclear Power Station, Unit No. 1 Response to I&E Bulletin No. 79-14 References (1), (2), and (3) provided status reports of the inspections required by I&E Bulletin No. 79-14.
This letter transmits an update report of Northeast Nuclear Energy Company's (NNECO) progress in verifying the seismic analysis input for safety-related piping systems.
The inspection and measurement phases of all accessible piping and supports contained in the 21 systems under investigation have now been completed.
The attachment provides the results of this work.
Based upon the high degree of confidence derived from the inspections that have been completed and the syrtem work /ISI inside the drywell as outlined in References (1), (2),
and (3) and within the attachment, NNECO reaffirms that the most prudent course available is the examination of the remaining inaccessible areas at the next refueling outage.
Any shutdowns which may occur due to maintenance problems will be used to perform as much work as possible inside the drywell. A preliminary schedule will be submitted in early December, 1979, for any reanalysis and any modifications that may be required based on evaluations of deviations from the original design.
Should you have any questions, please contact us.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY
'5 W y
i W. G. Counsil Vice President 1552 240 bE3 p
7912130
DOCKET NO. 50-245 ATTACIDiENT MILLSTONE NUCLEAR POWER STATION, UNIT NO. 1 RESPONSE TO I&E BULLETIN No. 79-14 1552 241 NOVDiBER, 1979
Twenty-one systems are included ~in the I&E Bulletin No. 79-14 investigations.
These systems contain in excess of 21,000 feet of seismic Category I piping and 1,300 supports in accessible and inaccessible areas.
The inspection and measurement phases of all accessible piping and supports contained in the 21 systems under investigation have been completed. This verification was conducted in accordance with I&E Bulletin No. 79-14 dated July 2, 1979, and revisions or supplements dated July 18, August 15, and September 7,1979. All system analysis review packages for accessible areas have been forwarded to our architect engineering firm for stress analysis and support / restraint review. The piping lengths and the number of supports associated with each system are presented in Table I.
Table II summarizes the verification effort to date indicating the proportion of accessible versus inaccessible piping and supports.
Throughout the inspection and measurement phase of this project, the need for accurate verification has been emphasized as well as the complete documentation of all deviations.
By the utilization of two man teams, documentation and installation reviews, compiling deviation lists upon completion of walkdowns, spot checking of records, there is high confidence in the accuracy of the inspections completed. The deviations identified to date are recorded by separating them into three distinct categories:
Category 1: Minor Deviations e Deviation will not adversely affect safe plant shutdown during a seismic event.
Deviation will not affect the results of the stress analysis.
e Field fixes in some cases alleviates deviation (loose turnbuckles, etc.).
e Category 2: Deviations Requiring Review Deviation requires review and potential reanalysis by stress analysis e
and support / restraint groups prior to final judgment as to severity of deviations.
e Dev.ations have been placed in this category by cognizant site engineer and stress analyst.
Category 3: Significant Deviation Deviation would affect safe plant shutdown during a seismic event.
e e Deviation in this category is classified as a nonconformance.
The following is presented as a summary of site inspection and measurement findings to date:
1552 242
. The vast majority of deviations are either Category 1 or 2.
e Of the 988 supports, two Category 3 deviations were discovered and e
corrected as follows:
1.
Service Water System a.
Installation of an anchor on 16"-SW-46 b.
Installation of a restraint on 12"-SW-47 and 8"-SW-28 c.
Installation of an anchor on 6"-SW-15 2.
Containment Cooling System a.
Installation of two anchors on 20"-CC-15a Af ter the initial engineering review uncovered the above nonconformances, recommendations to resolve the situation until a complete system reanalysis could be accomplished were forwarded to NUSCO and were implemented immediately, as described above. Technical Specifications and operational procedures were adhered to in all cases.
Of 988 supports reviewed, the locations requiring modifications represent 0.5 percent of the total number of supports reviewed.
Although the noncon-formances found were serious enough to require field modifications, the results of the total inspection and measurement effort have been excellent anc confidence levels for work in the inaccessible areas is still high. As outlined in previous submittals, (References (1), (2), and (3)), there are many items which support this high level of confidence for inaccessible inspections. Additionally, the following list identifies supports / restraints that have been dye penetrant checked at the welded attachment to the pipe during ISI examinations.
Main Steam Feedwater Isolation Condenser Low Pressure Coolant Inj ection MSR-H2 FWR-H2 IC-H21 MSR-H7 FWR-H4 CC-H101 MSR-H8 FWR-HS Cleanup W'ter CC-H100 a
MSR-H34 FWR-Hil CC-H104 MSR-H22 FWR-H14 CUW-H5 MSR-H14 FWR-H2O Recircula tion Core Spray Shutdown Cooling H9 CS-H1 SHC-H44 H10 CS-H56 SHC-H46 SS2 1552 243
. The following information represents the status of the systems presently under stress analysis and support / restraint review in the accessible areas.
If a particular system has all accessible areas inspected, it may not be possible to completely review the stress problem because portions may be inaccessible.
If this occurs, a review of the information available will be conducted; if it is deemed acceptable, the remainder of the review will be completed when the inaccessible portion is verified.
If it is found to be questionable as to the acceptability of the accessible portion, then field modifications will be made to whatever extent is necessary to meintain system integrity.
System Analysis / Review Status Service Water e Service water system in the reactor building and turbine building will be reviewed by stress analysis If reanalysis is required, NUSCO will e
perform Ebasco Support and Restraint Group will o
then review the supports utilizing the NUSCO stress information Reactor Building Closed Cooling W ter e
a Review to begin shortly Isolation Condenser e
Stress analysis of supply piping is acceptable NUSCO is to reanalyze vent and return e
i P ping e Results will be forwarded to Ebasco Support and Restraint Group for review Standby Liquid Control e System required reanalysis Reanalycis performed and system found e
acceptabi.e Support and Restraint Group now reviewing e
system Secondary Cooling System o Review to begin shortly 1552 244 System Analysis / Review Status Core Spray Review to begin shortly e
Containment Cooling /
Core Spray e Review to begin shortly Fuel Pool Cooling Systen Review to begin shortly e
Shutdown Cooling System Stress analysis review partially o
completed, review continuing Condensate System o Presently being reviewed Feedwater Sysrem e Accessible areas have been reviewed e Inaccessible area information is required to complete analysis properly Reactor Water Cleanup e Review to begin shortly Standby Gas Treatment e Presently being reviewed Control Rod Hydraulic System e
Review to begin shortly Nuclear Boiler e
System is presently inaccessible Radwaste 9ystem o Review to begin shortly Atmospheric Control System o Presently being reviewed Main, Extraction, and Auxiliary Steam e System is presently inaccessible Fire, Domestic, and Condensate Transfer Systems e Presently being reviewed Primary Containment Coding Service Water e Stress isometrics X-1, 2, and VI-6 being reviewed 1552 245
. e Stress isometric VI-5 had been reviewed and requires reanalysis.
NUSCO will perform the reanalysis Diesel Generator Fuel Oil System e Review to begin shortly Engineering reviews and stress analysis reviews accomplished by our architect engineering firm have not uncovered any nonconformances to-date, which have not either been corrected by the field modifications described previously or deemed acceptable by engineering review / analysis.
In all cases, safe shutdown of the plant during a postulated seismic event was not jeopardized.
Based upon the high degree of confidence derived from the inspections that have been completed and the system work /ISI inside the drywell as outlined in References (1), (2), and (3) and within this report, the most prudent course available is still the examination of the remaining inaccessible areas at the next refueling outage.
Preparations are underway to prepare to the maximum extent possible to conduct the surveys of inaccessible areas in the most expeditious and accurate manner possible.
1552 246
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Service Water 1260 1120 1120 140 140 9,7 92 92 5
4 100 Reactor Closed 2050 1300 1300 750 0
145 80 80 65 0
100 (toli;rr' Water Isolation 706 583 583 123 0
55 49 49 6
0 100 Condenser 300 225 225 75 0
37 30 30 7
0 100
. Standby Licuid Cbnizel 2464 2233 2233 231 0
123 115 115 8
0 100
. Secondary Coolinc Systern
. Cbre Spray 1700 1400 1400 300 0
110 80 80 30 0
100 (IPCI) 800 700 700 100 0
85 75 75 10 0
100
. Contain Cboling Core Sprav
. Fuel Pool 1160
, 1000 1000 160 0
63
' 63 63 0
0 100 Cbolina Svsten 790 620 620 170 0
68 56 56 12 0
100 y
. Shutdcwn miim mste
- 0. mndensate 3650 1500 1500 2150 100 238 120 120 118 7
100 Svsten f
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October 31, 1979 1
TABLE E MIIISIOE UNIT NO.1 IE 79-14 AS BUILT VERIFICATICN PIGECT INSPECTICN & MEASUREMENT SLM ITEM CLAVIITY PERCENT
'Ibtal Linear naet to be Investigated (Accessible & >==sible) 21,657 FT 100%
Accessible Piping 13,700 Fr 63%
Inaccessible Piping 7,957 FI 37%
'Ibtal Linear Feet Verified to Date Accessible Piping 13,700 ET 100%
Ina m safh19 Piping 240 FI 3%
'Ibtal NLeler of Swd & Restraints to be Investigated (Accessible & Inaccessible) 1428 100%
Accessible S w G & Restraints 988 69%
Inaccessible S W s & Pestraints 440 31%
'Ibtal SWG & Pestraints Verified to Date cx G & Restraints 988 100%
A:cessible Suw Inaccessible S W E & Restraints 0
0%
1552 248 4