IR 05000358/1979020
| ML19254E453 | |
| Person / Time | |
|---|---|
| Site: | Zimmer |
| Issue date: | 09/27/1979 |
| From: | Maura F, Streeter J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML19254E450 | List: |
| References | |
| 50-358-79-20, NUDOCS 7911010126 | |
| Download: ML19254E453 (6) | |
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U.S. NUCLEAR REGULATORY COMMISSION
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OFFICE OF INSPECTION AND ENFORCEMENT
REGION III
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Report No. 50-358/79-20 Docket No. 50-358 License No. CPPR-88 Licensee:
Cincinnati Gas and Electric Company 139 East 4th Street Cincinnati, OH 45201 Facility Name:
Wm. H. Zimmer Nuclear Power Station Inspection At:
Wm. H. Zimmer Site, Moscow, OH Inspection Conducted: June 13, 14 and July 23-26, 1979 Inspector:
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Approved B 'j. F. Streeter, (,h ef J2/2/
Nuclear Support Section 1 Inspection Summary Inspection on June 13, 14 and July 23-26, 1979 (Report No. 50-358/79-20)
Areas Inspected:
Special, announced inspection to review workman's com-plaint to the ASLB regarding work performed on the control rod blades; previous unresolved and noncompliance items; and pre-operational test pro-cedures. The inspection involved 36 inspector-hours on site by one NRC
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inspector.
Results:
No items of noncompliance or deviations were identified.
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DETAILS
1.
Persons Contacted,
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- E. Borgmann, Senior Vice President
- J. Schott, Station Superintendent
- P.
Hoffmeier, Technical Engineer
- J. Wald, Station Quality Engineer J. Woeste, Instrument and Control Engineer
- W. Schwiers, QA&S Principal Engineer R. Wood, QA&S Engineer M. May, GE Site Operations Manager
- L. Aiello, GE Quality Assurance Engineer J. Occoner, Reactor Control Inc.
The inspector also interviewed other licensee employees including members of the administrative, technical, operating, and QA&S staff; employees of the General Electric Company; and employees of Reactor Controls, Inc.
- Denotes those attending the exit interview of June 14, 1979.
- Denotes those attending the exit interviews of June 14 and July 26, 1979.
- Denotes those attending the exit interview of July 26, 1979.
2.
Licensee Action on Previous Inspection Findings (Closed) Deviation (358/79-01-03). Failure to tag critical valves during flushing of systems. The inspector found that the licensee has revised SU.ACP.03, " Conduct of Flushing Procedures," to require safety tagging on system boundary valves including critical valves and controls.
(Closed) Unresolved Item (358/79-06-07).
Poor communications during testing and flushing of systems. The inspector found that the licensee has revised SU.ACP.03, " Conduct of Flushing Procedures," to require that each system to be flushed be turned over to the Electric Production Department (EPD) in order to eliminate possible conflict regarding administrative control of the system. The EPD Quality Engineer will verify that the valve lineup is correct prior to any flushes. After completion of flushing operations on a system, the QA&S section issues a Stop Work Order to prevent inadvertent con-struction activities which could compromise the cleanliness of the system.
(Closed) Noncompliance (358/79-06-06D). Failure to follow procedure resulting in the washdown of the HPCS pump motor and flooding of the LPCS/ RHR-A pump room. The inspector has determined that the steps
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taken to correct item 358/79-06-07, above, are applicable to this
item. The inspector found that the flooded instruments were dried, cleaned and recalibrated. The motors were inspected for moisture, dried, meggered, and baaring oil changed if applicable.
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3.
Control Rod Interference Modification As a result of a workman's complaint to the Atomic Safety and Licensing Board (See Attachment A) an inspection was conducted regarding the grinding of a chamfer in the upper corner of the Control rod velocity limiter required by General Electric FDI No. 94/63000, Rev. O.
The modification was required to eliminate potential interference between the control rod and the fuel channel during the end of its insert travel. Prior to the inspection, the inspector interviewed the concerned workman by telephone on June 7, 1979, to ensure that his concerns were fully understood by the inspector. During taat con-versation the workman explained that his concern related to metal chips left inside the control rods. These chips had been generated during grinding done in late February 1979, to remove an oversized weld in the control rods. He further stated he was satisfied with the pre grinding cleaning job done to remove metal shavings left by the manufacturer.
The inspector reviewed the records of the modification required by FDI No. 94/63000, Rev. O, which was performed during the period of February 21-23, 1979. The inspector also interviewed Reactor Controls Inc., General Electric Co. and licensee personnel involved in the performance of the modification. The review revealed that:
a.
80 control rods required grinding of a chamber in one or more corners of the velocity limiter.
b.
All modification work was done with the control rods in the vertical position.
c.
During the initial work the corner holes and lower holes in the sheath were covered with tape. Because removing the tape and cleaning the adhesive from the shesth slowed the work the use of tape was replaced with six inch shim steck to cover a length approximately one foot high, d.
Polyethylene was used to cover part of the blades, but the actual length of the blade covered could not be absolutely dete rmined. The best estimate is that only the lower 3 to 4 feet were covered.
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Reactor Control Inc. and licensee personnel at the job claim no one complained about metal chips entetting the sheath holes during the modification. They also stated the chips traveled b}
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away from the blade due to the position of the blade and grinder,
and they personally did not see any chips in the blades after the modification was completed and prior to reinstalling the blades in in the reactor.
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At the inspector's request, a mockup of the grinding was made using a stainless steel 3 x 3 inch channel, half inch thick. Using the same grinder and burring tools used during FDI No. 94/36000, Rev. O, a chamfer approximately 1/4 inch in depth was machined in the upper corner of the channel. During the operation, the inspector held his hand over the channel to determine the direction of travel of the r+'al particles.
In addition, the metal being removed was collected determine the size of the particles. The inspector determined 1;at:
a.
Most particles traveled at an angle away from the blade with a few particles traveling in the near vertical direction. No particles traveled in the direction of the blade.
b.
The largest particle found was approximately 1/4 inch long x 3/64 inch wide. The thickness was a few mils. Most particles were the size of sugar grain particles.
Since particles were initially found in the control blades the inspector requested the licensee to consider:
a.
If a heat transfer problem would exist if enough metal chips were able to block the flow path between the absorber rods and the sheathing.
b.
The effect metal chips trapped between the absorber rods and the sheath could have on the life of the control rod, and how the problem, if any, could be monitored.
Following discussion, between the licensee, General Electric Co.
personnel and the inspector, it was determined that:
a.
There is no heat transfer problem even if enough metal chips succeed in blocking the flow path between the absorber rods and sheath.
b.
Relatively large chips trapped between absorber rods and the sheath, in the area where the control rod experiences the highest neutron flux exposure, could generate small cracks after the absorber rod becomes less ductile.
c.
General Eletric Co data presented to NRR this year indicates
that leaching of B C through ygli cracks does not start to occur until after 50% local B burnup occurs.
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d.
Theolddeggnlifeofacontrolrodwasdefinedastheti',e when 42% B depletion occurs over the top 25% of the con't The new design life changes the percent depletion.>f B}0 rod.
from 42% to 34%. Therefore, control rod blades are ref aced l
prior to the onset of B'C leaching.
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No items of noncompliance or deviations were identified.
4.
Review of Preoperational Test Procedures The following procedures were revie.;ed and found to meet the require-ments of Reg. Guide 1.68, FSAR commitments, Preoperational Startup Terting Manual, and Startup Administrative Control Procedures:
a.
PO-PC-1C, " Containment Local Leak Rate Test Type "C" Water Testing" b.
PO-RD-2, "CRD Hydraulic" No items of nancompliance or deviations were identill u.
5.
Startup Program Test Procedures The following draft startup procedures were reviewed as they compliment preoperational test procedure PO-RD-2:
a.
EX.05.1, "CRD Functional Testing" b.
EX.05.3, "CRD Friction Testing" c.
EX.03.4, " Partial Core Shutdown Margin" Initial comments discussed with the licensee during the review and exit interview were:
a.
Develop a schedule that commits CRD friction testing to be per-formed following fuel loading and prior to inital criticality.
b.
Include in the acceptance criteria for test EX.05.3 a limit for under piston pressure while inserting the control rod. This pressure limit shall be based on the prototype testing results.
c.
The acceptance criteria for test EX.05.03 shall be a level 1 instead of level 2.
The licensee agreed to consider all the comments. The inspector will again review these tests once they are in final form and have been approved by the licensee.
lio items of noncompliance or deviations were Identified.
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6.
Exit Interview
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The inspector met with licensee representatives denoted in Paragraph 1) on June 14 and again at the conclusion of the inspection on July 26, 1979. The inspector sumarized th.' scope and findings of the inspection.
Attachment: Attachment A 1 2 8 1
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