ML20044C661
| ML20044C661 | |
| Person / Time | |
|---|---|
| Issue date: | 04/13/1993 |
| From: | Richardson J Office of Nuclear Reactor Regulation |
| To: | Miller P WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| TAC-M83770, NUDOCS 9304270332 | |
| Download: ML20044C661 (3) | |
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Mr. P. E. Hiller Westinghouse Electric Corporation P. O. Box 355 Energy Center East-Bay 511 Pittsburgh, PA 15230 i
Dear Mr. Miller:
SUBJECT:
CLARIFICATION TO NUCLEAR REGULATORY COMISSION APPROVAL LETTER OF JANUARY 15, 1993 FOR TOPICAL REPORT NO. WCAP 12932, FULL RCS CHEMICAL DECONTAMINATION PROGRAM, REVISION 1, VOLUME 1 AND 2, TAC M83770 t
We have completed our review of the Westinghouse Owners Group (WOG) subject coments and have the following comments:
l WOG Question 1)
The cover letter third paragraph refers to the " approved version" and the " accepted version" of the Topical Report.
It is assumed that these terms have the same meaning.
Staff Response The two terms have the same meaning.
" Approved version" will be used solely in Rev. I of the approval letter.
WOG Question 2)
Page 2, Section 1.0 (Introduction) states, "there was some flaking of chrome-plating on stainless steels and shallow intergranular attack under the chrome-plating on 410 stainless steel". This statement should identify that there was interfacial attack under.the chromium plate on the 410 stainless steel.
Staff Response This will be corrected 89 Sev. 1.
WOG Question 3)
Page 2, Section 1.0 (Introduction) states, "the WOG recommended that the control rod drive mechanism (CRDM) be removed during decontamination.
The concern with the CRDN's was that they would be subject to fatigue damage with fuel out, and that corrosion, wear, flaking of chrome-plating in mating surfaces, and surface roughing could affect the functionality of the CRDM's."
This particular statement combines several concerns identified for both the control rod drive (CRD) shafts and the control rod drive mechanisms (CRDM) into the identified statement. This paragraph should identify that the Topical Report recommendation to remove the control rod drive shafts during the decontamination activities will alleviate the concerns dealing with reduced CRD shaft fatigue life and any CRD shaft damage resulting from flow induced vibration with the fuel removed. The remaining concerns which include corrosion, wear, flaking of chrome-O i
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s Mr. P. E. Miller plating on mating surfaces and surface roughing are associated with the CRDM's. These CRDM concerns were addressed and subsequently resolved during the CRDM latch assembly testing which was performed as part of the V.C. Summer Fuel Decontamination Program.
The results of this CRDM latch assembly testing verified that decontamination process reagents that would diffuse up through the CRDM standpipes (latch housing and rod travel housing) from the fluid flow below the vessel head and into the CRDM latch assembly during a decontamination operation would have little effect on the latch assembly components. Topical Report, WCAP-12932, Rev.1, provides the results of the V.C. Sumer Material Test Program.
Staff Reply Rev.1 of the Approval Letter will be revised to incorporate these coments.
WOG Question 4)
Page 10, Section 4.2, Significant Issues Covered in the Topical Report, item 7) identifies that the " Control rod drive mechanisms must be exercised in both the hot and cold conditions after completion of the decontamination process."
Based on the V.C. Sumer CRDM latch assembly test results, the current plant-specific procedure for Control Rod Exercise will be used following the decontamination operation.
Staff Reply The Generic Program Safety Analysis, (SECL-91-173) states on page 1.1-62 of the topical report that the " Control rod drive mechanisms must be exercised at both hot and cold conditions subsequent to decontamination process application." WOG proposes changing this procedure to the plant-specific procedure fer control rod exercise and this will require a change to the Generic Program Safety Analysis with a justification for the change (i.e. the V.C. Sumer data).
WOG Question 5)
The NRC approval letter refers to a typical 4-loop Westinghouse PWR plant. The topical report also applies to typical 2-loop and 3-loop Westinghouse plants.
Staff Reply The staff will incorporate the typical 2-loop and 3-loop plant in Rev.1 of the approval letter.
Sincerely, origing signedsy:
James E. Richardson James E. Richardson, Director Division of Engineering Office of Nuclear Reactor Regulation See next page for Distribution and Concurrence
Distribution:
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