ML20037B377
| ML20037B377 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 06/14/1978 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Brian Lee COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8009240806 | |
| Download: ML20037B377 (1) | |
Text
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Docket Nos. 5 10 50-237, 249, 50-254,- 0-265 Con 4onwealth Edison Courpany ATIN:
Mr. Byron Lee, Jr. ~
Vice President Post Office Box 767 Chicago, IL 60690 g,,gy,,,,,
Enclosed is IE Bulletin No. 78-09 which requires action.by you,with regard to your power reactor facilities with an operating' license.
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Should you have questions, regarding thin Bulletin or the actions -
required of you,; please contact this office.
Sincerely, f
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James G. Keppler Director
Enclosures:
1.
2.
List of IE Bulletins
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Issued in 1978 ec w/encis:
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Mr. B. B. Stephenson, Station Superintendent
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. Mr. N. Kalivianakis, ~
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Plant Superintendent
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NRC Form 318A (RIIE) (5-76) NRCM O2MO
.U. S. GOVERNMENT PRINTING OFFICE: 1978-253 811 secono 06
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C U.S. NUCLEAR REGULATORY COMMISSION l
OFFICE OF INSPECTION AND ENFORCEMENT REGION III
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June 14, 1978 IE Bulletin No. 78-09 BWR DRYWELL LEAKAGE PATHS ASSOCIATED WITH INADEQUATE DRYWELL CLOSURES Description'of Circumstances:
Upon completior. of the E. I. Hatch 1 plant refueling, the drywell head was reinstalled on April 1, 1978 and a local leak rate test (LLRT) was,_
successfully passed, p'r'oviding "no indication of a potential ~ problein aC the time. ' Subsequently,' during 'the containment integrated leak rats test (CILRT) at the E. I. Hatch 1 plant on April 4, 1978., high leakage around the.drywell head was,exp.erienced.. Af ter. the' high leakag'e rate was detect'ed, the co'ntainme'nt wa's Tep'reYsur'ize~d.' Prior to detensioning
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the drywell head bolts, a feeler gauge was used to determine that the clearance was greater where the leakage was occurring.
Upon retorquing the drywell head for a second LLRT and CILRT, the tightening sequence was started at the area of leakage and torque values of 1800 foot-pounds were used. Feeler gauge readings between the head and drywell were recorded. The second LLPT was pissed successfully and no leakage was indicated around the drywell head during the second and successful CILRT conducted at 59 pais.
Another instance was identified during the CILRT at Millstone Unit 1 on November 22-23, 1976, when both the drywell head and the drywell head manway cover " lifted" during a Type A test subsequent to successful Type B (LLRI) tests.
Based on this experience, it appears that the LLRT following each reinstalla~ tion of the drywell head or other closures, such as after a routiris rdfuelingCor. 'othe.r similar activity, cannot be the sole basis for assuri'tig's suitable degree of drywell closure leak tightness. It appears that there must be controls to ensure that drywell closures are made in a reproducible manner.
Action to be taken by all BWR power reactor facilities with an operating license or construction permit:
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IE Bulletin No. 78-09 June 14, 1978 1.
Determine if the procedural controls utilized at your facility are l
adequate to assure that drywell head reinstallations achieve a degree of leak tightness equivalent to that attained during the installation immediately preceding the last successful CILRT.
This determination should include, but not be limited to, con-sideration of the following:
Comparison of the applied bolt torque (or for turn-of-the-nut a.
technique, the number of flats on each nut / bolt after metal-to-metal contact has been achieved) after any head reinstal-lation to that used during the reinstallation verified by CILRT, including any additional local retightening needed to reach LLRT acceptance criteria.
b.
Comparison of head-flange clearances after any head reinstal-lation, to that used during the reinstallation verified by CILRT.
Determination of the suitability of the drywell head c.
gaskets for reuse.
d.
Determination of the maximum allowable bolt torques to avoid bolt overstressing conditions.
Determination of any special handling arrangements, e.
tightening sequence, gasket preparation, or other special considerations caused by unique facility circumstances such as a warped drywell head.
2.
Should your determination called for in Item 1 above demonstrate a need for procedural revisions, your response to this Bulletin should include a description of the changes to be made and a timetable for their implementation which must occur prior to the next drywell head closure.
3.
Identify other bolted containment closures that would tend to unseat on positive internal pressure and describe what actions are taken to ensure that adequate leak tightness would exist at an internal pressure of Pa.
4.
Within 45 calendar days of the date of issue of this bulletin, report in writing to the Director of the appropriate NRC Regional Office, the results of your review and your plan of action with regard to Item 1 through 3.
A copy of your report should be NN
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IE Bulletin No. 78-09 June 14, 1978 sent to the United States Nuclear Regulatory Commission, Office of Inspection and Enforcement, Division of Reactor Operations Inspection, Washington, D. C.
20555.
For all BWR power reactor f acilities with a construction permit, this Bulletin is for information only and no written response is required.
Approval by GAO, B180225 (R0072); clearance expires 7/31/80. Approval was given under a blanket clearance specifically for identified generic problems.
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I IE Bulletin No. 78-09 June 14, 1978 LISTING OF BULLETINS ISSUED IN 1978 Bulletin Subj ect Date Issued Issued To No.
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78-01 Flacmable Contact -
1/16/78 All Power Reactor Arm ~ Retainers in G.E.
Facilities with an CR120A Relays:
0L or.CE. ::
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78-02 ~
Terminal Block 1/30/78 All Power Iteactor Facilititt with an Qualification OL or Cr 78-03 Potential Explosive 2/S/78 All Ek'R Power Gas Mixture Accumula-Reactor Facilities tions Associated with with an OL or CP Bk'R Offgas System Operations 78-04 Environmental Quali-2/21/78 All Power Reactor fication of Certain Facilities with an Stem Mounted Limit OL or CP
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Switches Inside Reactor 5
Containment 78-05 Malfunctioning of 4/14/78 All Power Reactor Circuit Brecker Facilities with an OL or CP Auxiliary Contact Mechanie.-General Model CR105X 78-06 Defective Cutler-Hammer
'5/31/78 All Power Reactor Facilities with an Ha==er, Type M Relays with DC Coils OL or CP 78-07 Protection afforded 6/12/78 All Pcwer Reactor Facilities with an
\\by Air-Line Respirators and Supplied-Air Hoods OL, all class E and F Research Reactors with
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an OL, all Fuel Cycle
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Facilities with an F,
and all Priority 1 Material Licenseen
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