ML20138C744
| ML20138C744 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 10/11/1985 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19344C064 | List: |
| References | |
| GL-84-11, NUDOCS 8510230028 | |
| Download: ML20138C744 (7) | |
Text
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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.19101 SHIELDS L DALTROFF October 11, 1985 Docket No. 50-278 Mr. John F.
Stolz, Chief Operating Reactors Branch #4 Division of Licensing U.
S. Nuclear Regulatory Commission Washington, D. C.
20555 SUBJECTi Peach Bottom Atomic Power Station, Unit 3 Recirculation Inlet Safe End Crack Indications
REFERENCE:
(1)
- Letter, S.
L.
Daltroff, PECo, to J.
F. Stolz, USNRC, Dated December 14, 1984
Dear Mr. Stolz:
Peach Bottom Unit 3 was removed from service on July 14, 1985 for a refueling and pipe inspection outage and is expected to return to service in December, 1985.
This letter provides our plans ~ for returning Unit 3 to power operation with recirculation inlet safe end crack indications and is submitted for NRC-approval in accordance with 2(a) of Attachment 2 of Generic Letter 84-11.
In response to Generic Letter 84-11,'" Inspections of BWR Stainless Steel Piping", dated April 19, 1984, Philadelphia Electric Company (PECo) initiated an on-going program of weld inspections concerning Intergranular Stress Corrosion Cracking (IGSCC) mitigation.
As a result of indications discovered in welds in the Unit 2 reactor coolant primary boundary piping systems, PEco committed to additional inspections of welds in the
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reactor nozzle-safe end areas on Unit 3.
f On September 5, 1985 representatives of PECo and General Electric Company (GECo) met with the NRC technical staff.to
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discuss our findings and plans for continued operation relative pRol gan6C BC-ur t.
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Mr. John F.
Stolz October 11, 1985 Page 2 to the ten reactor recirculation inlet safe ends.
Reports concerning other pipe inspection findings and plans will be provided as soon as our inspections and evaluations are complete.
Results of the Unit 3 recirculation inlet safe end weld inspections indicate that eight out of the ten inlet safe ends have thin side crack indications and nine out of ten inlet safe ends have thick side crack indications at a location where the thermal sleeve is welded to the inside of the safe end.
All of the cracks are typical of IGSCC.
It has been determined by fracture mechanics analysis that Peach Bottom Unit 3 can continue operation for one full fuel cycle of 18 months without performing any inlet safe end repairs.
The engineering basis for this decision is presented in the attached General Electric Company report,- " Evaluation of Crevice Cracking in Peach Bottom Atomic Power Station Unit 3 Recirculation Inlet Safe Ends", (See Attachment 1).
contains information that is' classified Proprietary by GECo, as indicated in the attached Af fidavit.
The fracture mechanics evaluation of the inlet safe ends shows that continued operation is justified even when the worst conditions of reactor water chemistry, crack depth and crack length are assumed.
The calculated maximum operation time of 13,400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> at operating i
temperature is based on evaluation using the Peach Bottom Unit 3 lifetime water chemistry.
This time can be extended by maintaining improved water chemistry.
Proposed guidelines to be used to assure improved water chemistry for Peach Bottom Unit 3 Cycle ~7 are provided in Attachment 2.
Meeting these guidelines will ensure that the safe end performance will be' consistent with or better than that calculated.
These water chemistry guidelines are adapted from those prepared by the BWR Owners Group Water i
Chemistry Guidelines Committee.as included in the committee's j
final report dated April 1, 1984.
In addition to improving reactor water chemistry, PECo l
plans to install a crack growth verification system on the reactor recirculation system.
This system, which is described in, will provide additional assurance validating the crack growth rates assumed for the flaw evaluation.
It should be noted that the Peach Bottom Technical l
Specifications were amended on February 27, 1985, as Amendment l
Nos.- 105/108 for Unit 2 and 3 respectively, to reflect the l
guidance provided in Generic Letter 84-11 concerning reactor coolant leakage detection.
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Mr. John F. Stolz October 11, 1985 Page 3 i
Fur ther, Philadelphia Electric Company will replace the Unit 3 recirculation inlet safe ends during the next Unit 3 4
refueling outage using 316L safe. ends, with the tuning fork i
design thermal sleeve attachment.
J If you have-any questions or require additional l
information, please do not hesitate to contact us.
i Very truly yours, e'
kb f
m Attachments cc:
Dr. Thomas E. Murley, Administrator, Region I, USNRC T..P.
Johnson, NRC Resident Inspector i
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Docket No. 50-278 ATTACHMENT 2
' Proposed Water ChemistEy Guidelines for Peach Bottom 3 Operation These guidelines for water chemistry are. proposed for Peach Bottom 3 Cycle 7 operation.
Meeting these guidelines will assure j
that the safe end crack growth will be less than that expected from calculated crack growth.
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These guidelines are adapted from those supplied by the BWR-Owners Group Water Chemistry Guidelines Committee in their final l
report dated April 1, 1984.
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The proposed guidelines for reactor water chemistry during power operation equal to or greater than 25% are:
i Reactor water conductivity is limited to 0.3 uS/cm at 25 a.
degrees C.
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b.
If 0.3 uS/cm is exceeded, ef forts should be made to
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reduce the conductivity below the limit within 96 operating hours.
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c.
,If conductivity is not reduced below the 0.3 uS/cm level by normal operation methods within the next 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br />, an j
action plan should be developed and initiated to diagnose and remedy the situation.
d.
If conductivity exceeds 0.3 uS/cm at 25 degrees C for an
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accumulated time in excess of 55 days or for 10% of l
cycle 7 fuel operation (whichever is greater), either reduce the conductivity to 0.3 uS/cm at 25 degrees C, or reduce power below 25% within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
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h A period of 55 days corresponds to 10% of the expected length of Cycle 7 operation.
Operation above 0.3 uS/cm for 10% of the fuel cycle would result in a reduction in the ISI interval from 24,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> to no less than 18,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />.
This would not significantly i
erode the margin associated with the planned operation for 18
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calendar months.
Power lev'els below 25% power are excluded from the guidelines to permit condenser leak testing in the 20-25%
L range as needed for the improvement of water chemistry.
f Condenser leak testing using helium tracer gas has been found inef fective below 20% power.
However, time in excqss of I
chemistry limits at rated temperature and pressure with power less than 25% is not excluded from calculation of number of hours for ISI interval.
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l GENERAL ELECTRIC C0MPANY AFFIDAVIT I, Rick Artigas, being duly sworn, depose and~ state as follows:
1.
I am Manager, Licensing Services, General Electric Company, and have been delegated the function of reviewing the information described in paragraph 2 which is sought to be withheld and have been authorized to apply for its withholding.
1 2.
Summary Report, " Evaluation of Crevice Cracking in Peach Bottom Atomic Power Station Unit 3 Recirculation Inlet Safe Ends," NEOC-31086-P.
3.
In designating material as proprietary, General Electric utilizes the definition of proprietary information and trade secrets set forth in the American Law Institute's Restatement Of Torts, Section 757.
This definition provides:
"A trade secret may consist of any formula, pattern, device or compilation of information which is used in one's business and which gives him an opportunity to obtain an advantage over competitors who do not know or use it....
A substantial I
element of secrecy must exist, so that, except by the use of improper means, there would be difficulty in acquiring informa-
/l tion....
Some factors to be considered in determining whether given information is one's trade secret are:
(1) the extent'to i
which the information is known outside of his business; (2) i the extent to which it is known by employees and others involved in his business; (3) the extent of measures taken by him to guard the secrecy of the information; (4) the value of the i
information to him and to his competitors; (5) the amount of i
effort or mcney expended by him in developing the information; (6) the ease or difficulty with which the information could be i
properly acquired or duplii:sted by others.','
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4.
Some examples of categories of information which fit into the definition of proprietary information are:
a.
Information that discloses a process, method or apparatus l
where prevention of its use by General Electric's competitors without license from General Electric constitutas a competi-r tive economic advantage over other companies; b.
Information consisting of supporting data and analyses, includ-ing test data, relative to a process, method or apparatus, the application of which provide a competitive economic advantaga, e.g., by optimization or improved marketability; i i f
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t c.
Information which if used by a competitor, would reduce his expenditure of resources or improve his competitive position
-in the design, manufacture, shipment, installation, assurance of quality or licensing of a similar product; d.
Information which reveals cost or price information, produc-tion capacities, budget levels or commercial strategies of General Electric, its customers or ' suppliers; e.
Information which reveals aspects of past, present or future General Electric customer-funded development plans and programs of potential commercial value to General Electric; f.
Information which discloses patentable subject matter for which it may be desirable to obtain patent protection; g.
Information which General Electric must treat as proprietary according to agreements with other parties.
I h.
General Electric customarily maintains in confidence preliminary and draft material which has not been subject to complete proprietary, technical and editorial review but which is, cn occasion, furnished to the NRC staff on a confidential basis because it is General Electric's belief that it is in the public interest for the staff'to be promptly furnished with significant or potentially significant information.
5.
Initial approval of proprietary treatment of a document is made by the Subsection Manager of the originating component, the man most likely to be acquainted with the value and sensitivity of the information in relation to industry knowledge.
Access to such documents within the Company is limited on a "need to know" basis j
and such documents at all times are clearly identified as proprietary.
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6.
The procedure for approval of external release of such a document includes review by the Section Manager, Project Manager, Principal Scientist i
or other equivalent. authority, by the Section Manager of the cognizant Marketing function (or his delegate) and by the. Legal Operation for technical content, competitive effect and determination of the accuracy of
- l the proprietary designation in accordance with the standards enumerated above.
Disclosures outside General Electric are generally limited to regulatory bodies, customers and potential customers and their agents, suppliers and licensees only in accordance with appropriate regulatory provisiens or proprietary agreements.
t; 7.
The document mentioned in paragraph 2 above has been evaluated in-accordance with the above criteria and procedures *and has been found to contain information which is proprietary and which is customarily held in confidence by General Electric.
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8.
The information in the document mentioned in paragraph 2 discloses methodology, supporting test data, and analyses that form a basis for justifying the accuracy of crack growth projections in nuclear power j
plant materials.
It is information which falls substantially into j
several of the categories cited in paragraph 4., namely categories a.,
b.,
c., and e.
9.
The information to the best of my knowledge and belief, has consistently
.been held in confidence by the General Electric Company, no public disclosure has been made, and it is not available in public sources.
All disclosures to third parties have been made pursuant to regulatory provisions of proprietary agreements which provide for maintenance of the information in confidence.
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STATE OF CALIFORNIA
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COUNTY OF SANTA CLARA
) ss:
i Rick Artigas, being duly sworn, deposes and says:
That he has read the foregoing affidavit and the matters stated therein are true and correct to the best of his knowledge, information, and
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belief.
Executed at San Jose, California, this day of
,198_8,.
j General Electric Company i
/i Subscribed and sworn before me thisd_d+ day of5cotrJum 1985 l
ru N GE b
OFFICIAL SEA!,
NOTARY 7UBLIC, STATE gF CALIFORNIA
@ NoTARf PUBUC
- CAuroRNIA KAREN S VOGELHUBER SANTA CUUIA COUNTY My comm. expires DEC 30, 1988 l
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