IR 05000237/1986006
| ML17199F723 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/15/1986 |
| From: | Gautam A, Muffett J, Smeenge R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML17199F722 | List: |
| References | |
| 50-237-86-06, 50-237-86-6, 50-249-86-09, 50-249-86-9, NUDOCS 8604220136 | |
| Download: ML17199F723 (6) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION III
Reports Nb. 50-237/86006(DRS); 50~249/86009(bRS) Docket Nos. 50-237; 50-249 Licensee: Commonwealth Edison Company Post Office Box 767 Chi ta go, lL 60690 Lic~nses No. DPR-19; DPR~25 facility Name: Dresden Nuclear Power* Station, Units 2 and 3 Inspection At: Morris, IL Inspection Conducted: March 24-25j 1986 I A .. *s-:J.-G*a~utam ~ .J-\\ -_t_f) "# ~ nspec ors: ~ ~~
- Approved ~~
~~v..J .. ~;t\\-- By: J. W. Muffett~ CMe} \\'- Plant Systems Section Inspection Summary Inspection on March 24-25 1986 (Reports No.. 50-237/86006(DRS); 50-249/86009(DRS)) Areas.Inspected: Special announced (safety) inspection by two regional inspectors of potential environment qualification problems relative to electrical splices, control and power cables, and flexible liquid tight conduit installed in the Units 2 and 3 drywe 1 Results: No violations or deviations were identified; however, further NRC review is being conducted in the areas inspe~ted. '\\ .t-* -
..
DETAILS Persons Conta:-cted Common~ealth Edison (CECo) D. Scott, Station Manager
- J. Wujciga, Production Superintendent
- J. Brunner, Assistant Supe~intendeht, technical Services
- D. Adams, Regulatory Assurance
- G. Frankovich,.Environmental Quaiification Coordinator
- R. Stobert, Senior Quality Assurance Inspector US NRC B. Hare, Resident Inspector ln addition to the above, tbe insp~ctOrs interviewed and talked with other licensee personnel during this inspectio *Denotes those attending the exit interview on March 25, 198.
Potential.Environmental Qualification (EQ) Concerns in the Units 2 . and 3 Drywel l AMP Electrical Splices The NRC inspectors reviewed the qualification records for the AMP (vendor) electrical butt splices th~t had been ihstalled on the leads bf General Elettric FOl elettrical ~enetration ~ssemblies. These records showed that the splices were calculated to have a qualified life of 40 years plus one year post-accident Operabilit However, the 1 i cens.ee fouhd the._ i nsul at ion on.~. t-he splices in the Unit 2 drywe 11 . *to \\be' sever.ely, degraded and reqi:J*i re*d 'rep l aCelT)ent *with qualified Raychem
- ... >-{vendor) spi.ic;es during an October :1985.outag The NRC is concerned that the AMP splices may have a shorter qualified life than ca lcul at by the licensee andthat in the future, failures in the Unit 3 drywell
- which' still.has'AMP.spF~es,'couTd9ccur during plant operation causing e~uipment needed for ~larit shutdo~n*and mitigation of a design basis accident (DBA) to be rendered inoperabl During NRC interviews with licensee personnel.,these personnel reported:
No short Circuit or grounding failures had occurred in either unit relative to degrading of the insulation of the AMP splice * All Unit 2 drywell 10 CFR 50.49 designated EQ splices had been replaced with the qua l i fi.ed Raychem splice * Licensee inspections of the AMP splices in the Unit 3 drywell reported no insulation degradatio * The NRC inspectors reviewed the AMP electrical splices qualification package, CQD-015986, Revisi~n Files in the package included: review checklists for maintenance and surv.eillance; System Component Evaluation. Worksheet (SCEW); an_evaluation summary, by Bechtel; and an AMP Qualification Test Report, 110-11004, dated February 2, 198 The files indicated qualificatibn of environmehtally sealed AMP splices to requirements of IEEE 323-1974, IEEE 383-1974 and IE Bulletin 79-01 The licensee also.indicated that the AMP splices were qualified to requirements of the DOR Guideline (1) The qualification documents reviewed by the inspectors, qualified the AMP splices for LOCA parameters of 470°F, 89.2 psia, 100% relative humidity, chemical spray, and a total integrated dose of
- 2; 59 E08 Rads.. : These qua 1 i fiC:at i o,n,parameters are equa 1 to or
.exceed the p 1 ant/ specification, req1H remenls as identified on the SCEW.Th~ test~d.~plicei had also b~en thermally aged at 329°F for 21 days in order to simulate a 40 year life*at a temperature of 194°F(90°C).
The chemical. spr.ay and relative humidity test was performed*with th,e splices'_iristalled in a NEMA Type 3, ventilated enclosur The SCEW identifies that all EQ splites are located above flood leve The SCEW also ide~tified the splices qualified for a post-accident operability life greater* than one yea B~sed on the above qualification it was not clear why the insulati~n on installed splices had degraded within 15 years.. The licensee indicated that a Unit 2 high temperature event on June 1, 1970, may have contributed to the accelerated aging of the Unit 2 splice~. The licensee reported that splices were included in the post-event inspection and at that time were found to be satisfactor The maintenance requirements recommends. surveillance inspection every 10 years; however, the Unit 2 dr,YWell EQ splices were not in~pected again until 198 At that time, a total of 18 splices, out of bver 300 inspetted, we~e replaced (because of insulation embrittlement) at two of the penetration Surveillance of splices at other penetrations were not performed then because the licensee considered the 18 dama~ed splices to be an isolated cas In a surveillance inspection during January
- 1985, the licensee noted slight discoloration of splice "insula- *
- ti on but did not observe any cracks or damag A detailed examination of Unit 2 penetration AMP splices resulted in rep 1 acing all the Unit 2 EQ AMP sp 1 ices with qua 1 ifi*ed Raychem splices during the October 1985, outag During this examination the insulating sleeves were reported to be embrittled and pieces fell off when move Actual time-temperature measurements for the Unit 2 high temperature event were not recorde The licensee reported that the maximum estimated temperature.was 320°F for less than an hou The NRC inspectors determined that the licensee's OBA profile, for which the splice had been qu~lified, clearly envelo~ed the 320°F for less than an hour and that, severe degradation of the insulation on the splices should not have occurre The inspectors requested the licensee to determine, based on the qualification information ih their
,..
(2)
files, how many years of the qualified life of these splices were effected by the high temperature even Pending further NRC review of the qualified life, which takes into account the high temperature event, and experience accelerated aging of the Unit 2 AMP splices. this is considered an unresolved item (237/86006-0l(DRS)). In the review of the AMP splice qualification package, the inspectors observed that the splice samples tested were Model 52979, an environmentally sealed splice. During the visual inspection of the AMP splices installed in the Unit 3 drywell Penetration 204L, the NRC inspectors observed the splices had a clear yellow insulating sleeve and were marked 12-10* and 6-The licensee identified these splices as non-sealed type, AMP Model 53550- A Bechtel letter, dated December 19, 1984, (in the qualification file) addressed the similarity of the sealed and the non-sealed splices. This letter also identified the requirement that the non-sealed splices are to be shielded from moistur.e and direct chemical spray by a proper enclosur The SCEW identifies a proper enclosure as a NEMA Type 3, ventilated electrical box, or better. Item 6 of the AMP Splice Physical Details Che~ksheet requires a verification that the enclosure cover and gasket are properly installed and secure The licensee confirmed that NEMA Type 3 enclosures require a cover gasket: Contrary to the above, the enclosure* for Penetration 204L did not have a cover gaske The licensee confirmed that there were no gaskets in the enclosures of these splices in Units 2 and The licensee was informed that the lack of gaskets in the enclosures housing their AMP splices indicated they had been operating in noncompliance with requirements of 10 CFR 50.49 and the DOR Guideline CFR 50.49 Paragraph (f) states that electrical equipment important to safety must be qualified by testing an identical item under identical conditions or under similar conditions with supporting analysis to show that the equipment to be qualified is acceptabl Section 5.2.6 of the DOR Guidelines states that the equipment mounting and electrical or mechanical seals used during the type test should be representative of the actual installation for the test to be considered conclusiv The equipment qualification program should include an as-built inspection in the field to verify that equipment was installed as it was teste Particular emphasis should be placed on common problems such as protective enclosures and penetrations in equipment housings for electrical connections being left unsealed. Contrary to the above, the licensee did not provide gaskets on enclosures for penetration lead wires resulting in a condition where the AMP splices were not installed as tested and therefore not qualifie,* .... Based on the inspectors' review, the splices are part of the .circuit supplying power to motor operated valves required to oper~te during a OB Failure of the splices could cause *the _as.sod ated safetrre_l atec;t.equipment to be :inoperab.l The NRC-inspe-ctors concluded that this noncompliance related back to before the November 30, 1985 EQ deadline and has been corrected in.Unit 2, prior to the deadline_, by the installation of the qualified Raychem splice Unit 3 has been in an extended outage which began prior to the November 30, 1985, EQ deadlin The licensee's Station Nuclear Engi.neering Department has been requested to provide an evaluation for the Unit 3 AMP splices in enclosures without gasket Pending NRC review of this evaluation this matter i~ considered an uhresolved item (249/86009-0l(DRS)). Vulkene Cabl~s The NRC inspectors reviewed the qL1ali{ication records, EQ file CQD-018682, for the General Electric Vulkene control (SI-58743) and power (SI-58281) electrical cables used in the Units 2*and 3 drywell These records state that these cables are environmentally qualifi~d. in accordance with the DOR Guideliries and 10 CFR 50.49, for more than 40 years at 150°F _and one year post-accident operabilit Files in the qualification package included: review checklist for maintenance and surveillance, SCEW; and an evaluatibn summary by WESTEC Services, In The cables had. been qua l Hied to the LOCA conditions of 346°F, 127. 7 psia, 100% relative humidity, chemiC:al spray and a total i ntegnated dose of 2. 2Eb8 Rad the tested cables had bee Ii thermally aged at l65°C for i25 hours in order to simulate a 40 year life at a temperature of 150° Thermally aged specimens were irradiated to 2. 2E08 Rads which exceeds. the 40 year normal dose pl us one year post-acci den The qualification parameters are equal to or exceed the plant specification requirements as identified on the SCE The NRC inspectors had no further concerns.in this area at this tim D~maged Flexible Conduit ahd Cable Jackets in Unit 2 During the October 1985 Unit 2 outage the NRC SRI observed and photographed numerous examples of damaged flexible conduits and cable jacket degradation in the Unit 2 drywel From _the photographs the Regi'on III-NRC-inspec'tors were unable to de:t,ermine if the damaged flexible condL1it"or tabl* jacket degradation were associated with safety-related or EQ *designated equipmen Because Unit 2 was operating during this inspection, the inspectors did enter the Unit 2 drywel The NRC region inspectors. reviewed six work requests, for - the Unit *2 drywell, for repair and replacement of sealtite conduits, flexible conduits, cables and wires performed on EQ equipment during the October 1985 outag Several of the photographs showed damaged flexible conduit connected to temperature sensor The licensee stated that the drywell temperature sensors were not identified as EQ equipmen _... The licensee stated that similar repair and replacement work on non-safety systems had also been performed during this outage. It could not be determined if all the damage identified by the NRC SRI had been repaired or replace During this inspection the NRC region inspectors examined cables and flexible conduits in the Unit 3 drywel In the areas examined, the inspectors did not observed any degradation of cable jacket,s or damaged flexible conduits. Because of all the other work in progress, in the Unit 3 drywell, many of the flexible conduits were disconnected from equipment and their condition prior to disconnection could not be determine Those that were connected appear to be satisfactor Regarding degradation of the cable jackets, the jacket provides no electrical insulating function, but provides mechanical protection of the cable conductors during normal usage and installation. The ability of a cable to maintain electrical integrity during 0a LOCA or HELB is due only to conductor insulation properties. Vulkene cables used in the drywell of Units 2 and 3 were environmentally qualified both with and without the jacket. The jacket material and conductor insulation material used in the Vulkene cables are different and will therefore react different when they are exposed to the same environmen As long as the conductor insulation is not damaged or degraded, the Vulkene cables in Unit 2 drywell are environmentally qualifie Pending further NRC examination of the Vulkene cables in Unit 2, this is considered an open item (237/86006-02(DRS)). Open Items Open items are matters which have been discussed with the licensee, which will be reviewed further by the inspectors, and which involves some action on the part of the NRC or licensee or bot An open item disclosed during this inspection is discussed in Section. Unresolved Items An unresolved item is a matter about which more information is required in order to ascertain whether it is an acceptable item, an open item, a deviation, or a violation. Unresolved items disclosed during this inspection are discussed in Sections 2.a.(1) and 2.a.(2). Exit Interview The Region III inspectors met with the licensee representatives, denoted under Section 1, at the conclusion of the inspection on March 25, 198 The inspectors summarized the purpose and findings of the inspectio The licensee acknowledged this informatio The inspectors also discussed the likely informational content of the inspection report with regard to documents or processes reviewed by the inspectors during this inspectio The licensee did not identify any such documents/processes as proprietar }}