ML20072Q872
| ML20072Q872 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 08/31/1994 |
| From: | Richard Anderson NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9409120265 | |
| Download: ML20072Q872 (5) | |
Text
f Northem States Power Company 4
414 Nicollet Mall Minneapolis. Minnesota 55401-1927 Telephone (612) 330-5500 August 31, 1994 10 CFR Part 50 Section 50.55a US Nuclear Regulatory Commission Attn:
Document Control Desk Washington, DC 20555 MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Request for Review and Approval of Inservice Testine Program Relief Reouest PR-9 Enclosed for NRC staff review and approval is a new relief request (PR-9; HPCI, RCIC) necessary to support Revision 1 to the Monticello Third Ten Year Interval ASME Section XI Inservice Testing (IST) program. The relief request addresses an a'.'ternative to the code requirements concerning the ranges of instrumentation used for HPCI and RCIC pump testing.
The need for this relief request was brought to our attention during a combined IST and Check Valve inspection performed by A. Dunlop (NRC-Region III) and J. Colaccino (NRC-NRR) at the Monticello plant during the weeks of August 8 and August 22, 1994.
Revision 1 to the Monticello Third Ten Year Interval ASME Section XI IST program was submitted to the NRC staff on December 7, 1992.
Approval of the program, with comments, was granted by the staff on July 6,1993.
NSP's resolution of the NRC staff's outstanding comments was submitted to the staff in a letter dated February 15, 1994.
Included in NSP's February 15, 1994 submittal were revisions to Third Ten Year Interval IST Program relief requests PR-6 and SC-1, which are still undergoing NRC review.
In order to minimize the number of administrative revisions to our IST program, it is our intention to wait until the revisions to PR-6 and SC-1 and the new relief request PR-9 are all approved before we issue an l
update to Section 5.0 (" PUMP TEST PROGRAM AND RELIEF REQUESTS") to Monticello Third Ten Year Interval IST Program manual holders.
This letter contains no new NRC commitments, nor does it modify any prior commitments.
Please contact Marv Engen, Sr Licensing Engineer, at (612) 295-1291 if you require further information.
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Ro er O Anderson Director Licensing and Management Issues i
9409120265 940831 PDR ADOCK 05000263 l
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QSNRC NORTHERN STATES POWER COMPANY August 31, 1994 Page 2 c:
Regional Administrator - III, NRC NRR Project Manager, NRC I
Sr Resident Inspector, NRC State of Minnesota Attn: Kris Sanda i
Enclosure:
Relief Request PR-9 l
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RELIEF REQUEST NUMBER PR-9 System:
High Pressure Coolant Injection (HPCI)
Reactor Core Isolation Coolant (RCIC)
P&lD:
2 i
Function:
Inject Coolant into the Reactor Independent of AC Power Test Requirement from which Relief is Sought:
OMa-1988 Part 6 paragraph 4.6.1.2(a), analog instrument range shall not exceed 3 times the reference value.
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Basis for Relief:
10 CFR Part 50, Section 50.55a(a)(3), which states (in part):
" Proposed alternatives to the requirements of paragraphs (c), (d), (e), (f), (g),
and (h) of this section or portions thereof may be used when...
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(i)
The proposed allematives would provide an acceptable level of quality l
and safety,.. "
i inservice pump testing is performed in accordance OMa-1988 Part 6. The differential pressure for the HPCI and RCIC pumps is determined by subtracting the indicated suction pressure from the indicated discharge pressure. The HPCI pump suction pressure is read in the control room from instrument Pl-23-116, which is sent a 10 to 50 mAmp signal from local transmitter PT-23-100. The RCIC pump suction pressure is read locally from instrument PI-13-66. The relevant data for the instruments is as follows:
J INSTRUMENT PUMP RANGE REFERE. N RATIO j
VALUE (Range /
Ref Value)
PI-23-116 P-209 30" Hg Vacuum to 100 33.7 PSI 114.7/33.7 = 3.4 I
(See Note 1) 4
)
PT-23-100 P-209 10 to 50 mAmps 21.7 mAmps 40/11.7 = 3.4 (See Note 2)
PI-1346 P-207 30" Hg Vacuum to 100 33.7 PSI 114.7/33.7 = 3.4 PSI (see Note 1) l Note 1:
The vacuum range for the pressure indicators was converted to PSI for j
determining the ratio. 30 " HG Vacuum = 14.7 PSl; thus the RANGE = 100 +
14.7 = 114.7 PSI. The same principle was applied to the reference value (REF VAL). With a reference value of 19 PSI indicated on the instrument, the reference value used for the ratio determination is 19 + 14.7 = 33.7 PSI.
Note 2:
The pressure transmitter has a 10 to 50 mAmp range, or a span of 40 mAmps. The ratio for this instrument must be determined by reducing the J
reference value to its value on the 40 mAmp span (i.e., 21.7 mAmps equates to 11.7 mAmps on the 40 mAmp span).
The code requires the instrument range to be less than 3 time the test parameter reference value. The 2% code allowable instrument tolerance is then taken from this range requirement. The same instrument calibration tolerance can be applied to these instruments by simply calculating the code required tolerance from the code equivalent range as follows-i INSTRUMENT REFERENCE CODE EQUIVALENT 2% OF CODE VALUE RANGE EQUIVALENT RANGE PI-23-116 33.7 PSI 3 x 33.7 = 101 PSI i2 PSI PT-23-100 21.7 mAmps 3 x 11.7 = 35.1 i 0.7 mAmps i
mAmps PI-13-66 33.7 PSI 3 x 33.7 = 101 PSI i2 PSI The existing instrument calibration tolerances are 2 PSI for the pressure indicators and i j
0.8 mAmps for the pressure transmitter. The calibration history for these instruments 4
5
v i
shows that they easily meet these existing tolerances. Recent calibration records show the instruments' as-found accuracy of 1% or less of the code equivalent range.
Under the provisions of 10 CFR 50.55a(a)(3), this attemative to the Code requirement is proposed in that the altemative provides an equivalent level of quality and safety. The proposed altemative satisfies the code intent in that the accuracy of the instrumentation to assess the operational readiness of the HPCI and RCIC pumps will be maintained within Code requirements.
1 Altemative Testing:
The instruments identified above will be calibrated to 2% of a code equivalent range. The code equivalent range will be calculated by multiplying the test parameter reference value by thre. For pressure indicators PI-23-116 and Pl-13-66 this will result in a allowable tolerance equal to 12 PSI on the output or10.7 mAmps on the input (Note: PI-23-116 may be calibrated by determining the mAmps input signal required to establish a set PSI output).
Pressure transmitter PT-23-100 will be calibrated to 0.7 mAmps for the reasons discussed above.
Approval:
Approval for the 3rd ten year interval is pending.