ML20211G642
| ML20211G642 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 06/12/1986 |
| From: | Hinson C Office of Nuclear Reactor Regulation |
| To: | Walker R PUBLIC SERVICE CO. OF COLORADO |
| References | |
| NUDOCS 8606200041 | |
| Download: ML20211G642 (7) | |
Text
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June 12, 1986 Docket No. 50-267 Mr. R. F. Walker, President Public Service Company of Colorado Post Office Box 640 Denver, Colorado 80201-0840
Dear Mr. Walker:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - FORT ST. VRAIN (FSV) -
PRESTRESSED CONCRETE REACTOR VESSEL (PCRV) TENDONS
Reference:
1.
FSV Report, " Tendon Surveillance," March 18, 1985 (P-85084) 2.
FSV Report, "PCRV Tendon Interim Surveillance and Status i
Report," January 22,1986(P-86042)
The staff has reviewed the two Public Service Company of Colorado (PSC) reports referenced above and has determined that additional information is needed to complete this review.
Enclosed are eleven questions that define the additional information needed for this review. Although the staff discussed these questions with PSC during our visit to FSV on April 23-24, 1986, we request that you respond to these questions formally in writing 45 days from the date of this letter.
If you have any questions, please contact Charles Hinson at (301) 492-7930.
The information requested in this letter affects fewer than 10 respondents; therefore, OMB clearance is not required under P.L.96-511.
Sincerely, original signed by Charles S. Hinson, Project Manager Standardiza+1on and Special Projects directorate Division of PWR Licensing-B
Enclosure:
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WASHINGTON, D. C. 20555 June 12, 1986 Docket No. 50-267 Mr. R. F. Walker, President Public Service Company of Colorado Post Office Box 840 Denver, Colorado 80201-0840
Dear Mr. Walker:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - FORT ST. VRAIN (FSV) -
PRESTRESSED CONCRETE REACTOR VESSEL (PCRV) TENDONS
Reference:
1.
FSV Report, " Tendon Surveillance," March 18, 1985 (P-85084) 2.
FSV Report, "PCRV Tendon Interim Surveillance and Status Report," January 22, 1986 (P-86042)
The staff has reviewed the two Public Service Company of Colorado (PSC) reports referenced above and has determined that additional information is needed to complete this review.
Enclosed are eleven questions that define the additional information needed for this review. Although the staff discussed these questions with PSC during our visit to FSV on April 23-24, 1986, we request that you respond to these questions formally in writing 45 days from the date of this letter.
If you have any questions, please contact Charles Hinson at (301) 492-7930.
The information requested in this letter affects fewer than 10 respondents; therefore, OMB clearance is not required under P.L.96-511.
Sincerely, h
w t
Charles S. Hinson, Project Manager Standardization and Special Projects Directorate Division of PWR Licensing-B
Enclosure:
As stated cc w/ enclosure:
See next page 1
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Mr. R. F. Walker Public Service Company of Colorado Fort St. Vrain cc:
Mr. D. W. Warembourg, Manager Albert J. Hazle, Director Nuclear Engineering Division Radiation Control Division Public Service Company Department of Health of Colorado 4210 East lith Avenue P. O. Box 840 Denver, Colorado 80220 Denver, Colorado 80201 Mr. David Alberstein,14/159A Mr. J. W. Gahm, Manager GA Technologies, Inc.
Nuclear Production Division Post Office Box 85608 Public Service Company of Colorado San Diego, California 92138 16805 Weld County Road 19-1/2 Platteville, Colorado 80651 Mr. H. L. Brey, Manager Nuclear Licensing and Fuel Division Mr. L. W. Singleton, Manager Public Service Company of Colorado Quality Assurance Division P. O. Box 840 Fort St. Vrain Nuclear Station Denver, Colorado 80201 16805 Weld County Road 19-1/2 Platteville, Colorado 80651 Senioi Resident Inspector U.S. Nuclear Regulatory Commission P. 0. Box 640 Platteville, Colorado 80651 i
Kelley, Stansfield & 0'Donnell Public Service Company Building Room 900 550 15th' Street Denver, Colorado 80202 Regional Administrator, Region IV U.S. Nuclear Regulatory Consnission 611 Ryan Plaza Drive,-Suite 1000 Arlington, Texas 76011 Chairman, Board of County Commissioners of Weld County, Colorado Greeley, Colorado 80631 Regional Representative Radiation Programs Environmental Protection Agency 1800 Lincoln Street Denver, Colorado 80203 i
l
Request for Additional Information Fort St. Vrain - Tendon Surveillance I.
Questions pertaining to the report " Tendon Surveillance," submitted to NRC with PSC letter P-85084 dated March 18, 1985.
General Question 1.
Provide the specific outline of the extent of the intended mandatory engineering evaluation. The response should describe the time limit for completion as well as more information with regard to the depths and methodology of the evaluation.
Specific Questions 1.
Section 1.4 - Margin of Safety Describe the type of analysis performed to determine the number of tendons that could fail without reducing the safety factor against failure at 845 psig.
In your response, specify the i'
postulated loading conditions, the compliance with the FSAR Section E.1
" Prestressed Concrete Reactor Vessel Design Criteria," the computer programs used, and other pertinent information which illustrates the depth and completeness of the analysis.
2.
Section 3 - Analyses of Cause of Corrosion Indicate what remedial action was undertaken by the Central Electricity Generating Board (CEGB) in the United Kingdom as a result of the corrosion problem CEGB experienced and to what extent such action has been adopted by PSC.
3.
4.1.1.6.1 - Examination of Sample Wires The proposed acceptance criteria are noncommittal with respect to installation of additional sample wires.
Specify whether, and describe how and when, more of the sample wires will be installed.
4.
4.1.2.6.2 - Tendon Atmosphere Sampling The proposed criteria are not specific as to whether tendon sampling is to be conducted or not and, if so, whether an inert gas such as nitrogen will be utilized. The proposed installation of a nitrogen blanket is discussed in Section 4.5, but Section 4.1.2.6.2 fails to make a firm commitment to utilize an inert gas atmosphere in the l
tendon tubes to inhibit corrosion.
Indicate if an inert gas will be used and if so, what measures will be taken to prevent its leakage.
j*.
\\ 5.
4.1.2.6.3 - Examination of Anchor Assemblies a)
This section lacks specific criteria regarding procedures and evaluation of the examination of anchor assemblies; therefore the proposed criteria cannot be meaningfully assessed.
b)
Provide the basis for the assumption of uniform degradation of all tendons.
c)
Explain how an evaluation of wire failure criteria will be perfonned.
j 6.
4.1.2.6.4 - Liftoff Testing a)
This section states that a tendon is considered acceptable if
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its tension is above the minimum design level. A more
' appropriate criterion is that a tendon is acceptable if its tension is within the specified limits at the time of the liftoff test. An engineering evaluation to determine the cause of deviation from the above criterion, and any remedial action j
to be taken, should be done within an appropriate period of time following the test when the above criterion is violated.
Recommendations contained in Regulatory Guide 1.35 could be j
used for guidance.
I b)
Provide the pertinent information regarding the equipment used l
in tendon liftoff testing, as well as the applicable procedures, the equipment calibration methods, and training and j
qualification of the personnel performing the tests.
7.
4.6 - Replacement and Testing of Existing Tendons l
i There is an apparent contradiction in the proposed tendon testing i
program. The last paragraph on p. 4-18 states that:
"A chemical l
solvent will be injected through a tendon tube to remove the old i
grease from a tendon." A paragraph on p. 4-19 states that:
"A tendon shall be installed, if possible, with the old grease intact."
l Please clarify this apparent contradiction.
II. Questions pertaining to the "PCRV Tendon Interim Surveillance and Status Report" dated January 1986.
1 1.
Section 2.1, p. 3 of 52 i
The paragraph describing " Control Tendons" states that:
" Selection of control tendons is based on the observance of corrosion..."
Review of Table 2.3-1 discloses that there are a number of tendons l
whichhaveanumberofwiresbroken(e.g.BILU3(16and20),BILU4 i
(28 and 3), and CO 2.5 (3 and 16)) but have not been selected as
" control tendons." Explain your reasoning for not including'the above damaged tendons as part of the " control tendon" group.
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Section 2.3.4, p. 32 of 52 It is noted that, for a period of time, several of the tendons did not have valid cell readings.
Indicate if any corrective measures have been undertaken or planned which would rectify this situation.
If not, provide justification for the adequacy of your load cell surveillance program.
III. Question Pertaining to the FSAR 1.
Section 5.13.8 of the FSAR states that if there is any deterioration of the wire, the tendon in question will be detensioned and pulled out for detailed examination. Since there is already evidence of an extensive degradation of tendons, describe the future action planned which would satisfy this FSAR commitment.
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