ML20052B795
| ML20052B795 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 04/19/1982 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| EQC-82-250, TAC-10816, NUDOCS 8205030581 | |
| Download: ML20052B795 (6) | |
Text
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)SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT [] 6201 S Street, Box 15830, Sacramento, California 95813; (916) 452-3211 April 19, 1982 EQC 82-250 m
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sf DIRECTOR OF NUCLEAR REACTOR REGULATION ATTN MR JOHN F STOLZ CHIEF f
Y S OPERATING REACTORS BRANCH 4 U S NUCLEAR REGULATORY COMMISSION WASHINGTON DC 20555 n oR 3 0 ESZ" To C gm m c rcmG3 gg% r.u Ui] Il q*
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DOCKET 50-312 RANCHO SECO NUCLEAR GENERATING STATION g
8 UNIT N0 1 t
REFERENCE:
Stolz letter to Mattimoe, dated 3-15-82 The submittals addressing the inservice inspection portion of the Rancho Seco ISI/IST Program are complete as listed in tabulation on your Enclosure 1.
We are submitting one additional request for relief, NDE-13, attached. This should /
complete the requests to be in accordance with the 1974 edition of Section XI of the ASME Code through the S-75 Addenda.
It is not our intent to use later editions / addenda of the code throughout this interval, although they are referenced as justification in some " basis for Relief Request" statements, it should be noted that the "10 year" reactor vessel examination is planned during the September 1982 defueling outage, prior to the end of this inspec-tion interval, June 1986. This has been discussed previously with the NRC staff and will be discussed in much greater detail prior to the outage, in response to Enclosure 2, Request for Additional Information, a separate v
attachment has been prepared.
Any futher detailed questions may be hanMed through Mr. Jack Uh1 of my staff.
'l i kL f oi 7
.S John J Mattimoe Assistant General Manager j
j and Chief Engineer
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Enclosure 8205030 58/
AN EtECTRIC SYSTEM S E R V. N G MORE THAN 600,000 IN THE HEART OF CAllf0RNIA
John F. Stolz April 10, 1982 l
In response to Enclosure 2, Request for Additional Information:
1.
Reactor Vessel, CRDM Mechanism Bolts and Control Pod Housing Fianne Rings-(I tems B1.11.1 and B1.11.2; Category B-G-2)
Code relief is explained in HDE-3 (Ref. 1) which states:
" CODE REO.UIREMENT:
Visual examination of 100% of Control Rod Drive Mechanism (CRDM) bolting during the interval.
BASIS FOR RELIEF REO.UEST:
Bolting is only accessible for examination when the CRDM'is removed.
Category B-0 requi res that 10% of the perioheral CROMs (i.e., 3) be removed for examination.
ALTERNATE EXAMINATION: All bolting from removed CROMs will be visually examined."
QUESTION This is taken to mean that only bolting on 10% of the peripheral CRDMs plus
.any CRDMs which need removal for maintenance reasons will be examined.
The following additional information is requested:
1.
Why are the flarge rings included in a Category B-G-2 relief request?
2.
Please providt evidence that all bolting on in-place CRDMs in inaccessi-ble.
Are any or all bolts on peripheral CRDMs accessible? What about bolts on CRDMs adjacent to those that have been removed for examination or maintenance?
AHSL'E R The interpretation regarding inspecting 10% of the peripheral bolting is incorrect.
"All bolting from the removed CRDMs will be visually examined."
1.
The flange rings are actually_ a pair of semi-circular rings with threaded holes that comprise the " nut" portion of the-bolted closure.
Hence, they are in Categary B-G-2 and included in the request for relief.
4 2.
The bolts are approximately 17 feet below the deck of the cylindrical Head. Se rvice St ructure.
Seismic plates at the deck elevation obviate
. visual examination of the~ bolt heads.from this location.
The flange rings are positioned under the CRDM-to-head nozzle flanges and are not accessible.
I
John'F. Stolz April 19, 1982 ANSWER 2.
(Continued)
There are eleven 12" diameter and one elliptical 12"x18" holes around the base of the service structure. A few of the outboard bolts on the peri-pheral closures could be examined af ter the cooling fans are removed from these 12" holes.
We have greater confidence in relying upon the pressure test at 2255 psi that is performed af ter every opening of the RCS to sub-stantiate the closure integrity, than visually examining a few of the 552 bolts every ten years.
It would be possible to view approximate 1.y 16 bolt heads via the remote T.V. on the adjacent closures to a removed CRDM.
Again, we feel the pressure tests to be more effective.
Af ter two CRDMs were removed for maintenance during the 1981 re fuel ing outage, all 16 bolts were examined and there was no evidence of any service induced problems.
2.
Pump Pressure Boundary, Pump Casing Weld (I tem B5.6.1 ; Category B-t-1)
Code relief is explained in NDE-7 (Ref. 1) which states the following:
" CODE REO.UIREMENT:
Category B-L-1 of TaSle IWB-2600 requi res that a volumetric examination be performed on pump casing welds.
BASIS FOR REllEF REO.UEST:
No techniques are currently available for volumetric examination of thick stainless steel castings.
ALTERNATE EXAMINATION:
None until practical techniques are developed."
QUESTION What state-of-the-art techniques are you studying and developing to comply with the above requirement?
ANSWER e
We are considering utilizing a device comparable to the MINAC System developed by EPRI and administered by J. A. Jones Applied Research Co.
Since Oconee Units II & Ill have pump casings of the same design, we anticipate coordinating the techniques and equipment between the two sites.
\\
I John F. Stolz April 19, 1982 i
QUESTION 3
Under the change in Regulation 10 CFR 50.55a effective November 1,1979, the 4
ISI program when finally approved, will cover the last 80 months of the cur-rent 10 year inspection interval, i.e., from October 1979 to June 1986.
Does this result in any changes you wish to make in the relief requests? Do you require other 151 relief?
ANSWER The additional relief request, NDE-13, is submitted herewith.
I 1
J
5-12:
NDE 13 CODE EM COMPONENT IDENTIFICATION PAGE ITEM NO.
CLASS CATEGORY REACTOR VESSEL, V-200 1
3 Bl.12.1 B-ll CODE REQUIREMENT:
For vessel support skirts, the volumetric examination performed during each inspection interval shall cover at least 10% of the circumference of the weld to the vessel.
BASIS FOR RELIEF REQUEST:
Thr: high radiation levels, 2 R/Hr outside the insulation surface, make performance of this examination contradictory to ALARA principles.
The current edition of Section XI excludes this weld from examination, since it does not fall with the IWB boundary.
See attached Fig. IWB-2500-14 with dimensions marked.
ALTERNATE EXAMINATION:
None.
9
n yig. IM B-2.#14 SEC110N XI-DIVI 51GN 1
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