IR 05000282/1985011

Insp Rept 50-282/85-11 on 850415-0502.Noncompliances Noted: Failure to Have Adequate Containment Integrated Leak Rate Test Procedures & Failure to Perform Repairs to Penetrations Prior to Type a Test

ML20128M791
Person / Time
Site:	Prairie Island
Issue date:	05/17/1985
From:	Guldemond W, Hare S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20128M752	List: IR 05000282/1985011 IR 05000416/2005002 ML20128M748
References
50-282-85-11, NUDOCS 8506030082
Download: ML20128M791 (9)

Text

., .

.

U.S. NUCLEAR REGULATORY COMMISSION

REGION III

Report No. 50-282/85011 Docket No. 50-282 License No. OPR-42 Licensee: Northern States Power Company 414 Nicollet Mall Minneapolis, MN 55401 Facility Name: Prairie Island Nuclear Generating Plant, Unit 1 Inspection At: Red Wing, MN Inspection Conducted: April 15 through May 2, 1985 Inspector:

h S. M. Hare

& 4 r s'- / 7 -B s '

'

Date P:=1 Approved By: . G. Gu emond, Chief .5 - / 7-Ar Operational Programs Section Date Inspection Summary Inspection on April 15 through May 2,1985 (Report No. 50-282/85011(DRS)

Areas Inspected: Routine, announced inspection by a region based ins licensee event reports; containment integrated leak rate test results; (CILRT)pector of Technical Specifications; local leak rate test procedure and results; and as found CILRT results. The inspection involved 18 inspector-hours onsite by one NRC inspector including 2 inspector-hours onsite during off-shifts. Thirty-four inspector-hours were expended in the Region III Offic Results: Of the five areas inspected no items of noncompliance'or deviations were identified in three areas. In the remaining areas three items of noncompliance were identified including three examples of failure to have adequate CILRT V (paragraphs procedures 3.a., 3.d.(1), andas3.d.(2)

required by)10

failure to CFR followPart 50, Appendix procedures as B, Criterion required by Technical Specification 6.5 (paragraph 3.d.(2); and failure to determine the as-found containment leakage as required by 10 CFR Part 50, Appendix J and ANSI N45.4-1972 (Paragraph 6).

g[

G P

,

-

.

DETAILS 1. Persons Contacted

+*E. Watzl, Plant Manager

+.D. Mendele, Plant Superintendent Engineer

+.*A. Smith, Consulting Schedule Engineer

+M. Gruber, Production Engineer-

+.*B. Frazier, Production ILRT Engineer

. *A. Hundstadt, Senior Production Engineer NRC

+.*J. Hard, Senior Resident Inspector

+.*P. Hartman, Resident Inspector

. *W. Gudlemond, Chief, Operational Programs Section

• Denotes personnel present at the April 16, 1985 teleconferenc . Denotes personnel present at the April 17, 1985 teleconferenc + Denotes those attending the May 2,1985 exit intervie . License Event Report Followup (0 pen) Licensee Event Report 85-05-0 Item (282/85011-LL): One containment isolation valve failed its local leak rate test. At the time of the inspection, the licensee had not prepared a supplemental detailed report as committed to in Revision 0 of this LE . Containment Integrated Leak Rate Test (CILRT) Procedure Review The inspector performed an in-office review of procedures SP-1071 (2),

(4) and (5) associated with the perfonnance of the CILRT for confor-mance with 10 CFR Part 50, Appendix J and ANSI N45.4-1972 requirement The inspector's comments with the exception of consnents pertaining to temperature surveys and data rejection criteria were incorporated into the procedures prior to the performance of the CILR The inspector noted to the licensee prior to the performance of the CILRT t1at ANSI N45.4 paragraph 7.2 requires containment area surveys be performed to verify the proper placement of test instrumentatio The inspector also noted that if containment conditions change during the course of the test (e.g., circulating fans trip off) or between tests (i.e., no heat loads versus heat loads), a containment area survey must be reperformed. The lack of temperature survey require-ments resulted in the licensee not performing a temperature survey as required by ANSI N45.4-1972. Failure of the licensee's CILRT proce-dure (s) to adequately reflect the temperature survey requirements of ANSI N45.4-1972 is an example of a noncompliance (282/85011-01A(DRS))

against 10 CFR Part 50, Appendix B, Criterion m

'

- .

,

In addition, the inspector noted'to the licensee that during a CILRT, it may be necessary to reject or delete specific sensors or data points due to drifting / erroneous sensors or data outliners. At the time of the inspection the Ifcensee's procedure (s) did not have  :

data rejection criteria for drifting / erroneous sensors. This is an '

open item (282/85011-02(DRS)) pending licensee action to resolve '

this issu Summary of Appendix J Requirements l

To ensure the licensee's understanding of Appendix J requirements t

the inspector had numerous discussions with licensee personnel during the course of the inspection. The following is a summary of the issues discussed with the license (1) Whenever penetration configurations during a CILRT deviate from the ideal, the results of LLRTs for such penetrations must be  ;

added as a penalty to the CILRT results at the 95% confidence level. An acceptable penetration-leakage penalty is determined using the " minimum pathway leakage" methodology. . This methodology ,

is defined as the minimum leakage value that can be quantified  ;

'

through a penetration leakage path (e.g., the smallest leakage of two valves in series). This assumes no single active failure of redundant leakage barriers. Additionally, any increase in containment sump, pressurizer, or steam generator level during -

the course of the CILRT must be taken as a penalty to the CILRT results. If penalties exist, they must be added (subtraction is never permitted) to the upper confidence level of the CILRT result (2) The Type A test length must be 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or longer to use the mass point method of data reduction. If tests of less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> are planned, the Bechtel Topical Report, BN-T0P-1, must be '

followed in its entirety except for any Section which confifets with Appendix J or Technical Specification requirements. For either methodology, the acceptance criterion is that the measured  :

leakage at the 95% upper confidence limit must be less than 75%

of the maximum allowable leak rate for the pressure at which the test was performe !

,

(3) For the supplemental test, the size of the superimposed leak ,

rate must be between 0.75 and 1.25 times the maximum allowable leak rate La or Lt. The supplemental test must be of sufficient duration to demonstrate the accuracy of the test. The NRC looks .

for the results stabilizing within the acceptance criteria, not'

just being within the acceptance criteria. Whenever the BN-T0P-1 methodology is being used, the length of the' supplemental test

,

cannot be less than approximately one half the length of the

,

CILRT and the BN-TOP-1 method of data reduction must be used.

! i

!- (4) An acceptable method for determining if the sum of Type B and C

'

tests exceeds the 0.60 La Appendix J limit is to utilize the i' " maximum pathway leakage" metho This methodology is defined l'

as the maximum leakage value that can.be quantified through a

,

i s

+ - - e <-e-v- p ,+m-mmtveg me,gg.,-p-rm , a--,m,.,,vyme,-y-y--,p-em,e,-,-,m,yog---u-e-w r mm m-m -g -- .- o-my,qy p,,,ww g e- ,wm , g emm -g e< ~.ge w ,-, p gemsw ~ m pp m, , - r,+ n s,mp ow - r -g --w -

__ __-_ - - _ _ _ _

e *

}

penetration leakage path (e.g., the larger, not total, leakage of two valves in series). This assumes a single active failure of the better of two leakage barriers in series when performing Type B or C test (5) Future periodic Type A, B, and C tests must include both as found and as left results. In order to perform repairs prior to a Type A test, an exemption from Appendix J requirements should be obtained from NRR. The exemption should state how the licensee plans to determine the as found condition of the containment sinca local leak rate tests are being performed prior to the CILRT. An acceptable method is to commit to add any improvements in leakage rates which are the result of repairs or adjustments (ras) using the " minimum pathway leakage" methodology, c. Instrumentation The inspector performed a post test review of the instrument calibration data associated with performing the CILRT. A multipoint calibration of all instrumentation was performed. Correction values were generated based on the difference between measurements of resis-tance from an NBS verified resistance box and actual resistance. All corrections were placed as an array or equation into the CILRT compute The following instrumentation was used in the CILRT:

Tyn Quantity RTDs 18 Flowmeter 2 Pressure Gauge 2 Dewcells 6 d. CILRT Review The inspector performed a review of the test data and the test log against the requirements of 10 CFR Part 50, Appendix J and ANSI N45.4-1972. The inspector noted the following:

(1) The licensee was attempting a short duration CILRT in accordance with the Bechtel Topical Report (BN-TOP-1). When performing a BN-TOP-1 short duration test, the leakage obtained at the upper 95 percent confidence level is considered the containment's leakage and should be reported as such. Contrary to this requirement the licensee terminated the measured leakage phase of the test using the leakage acceptance criteria of BN-TOP-1 without satisfying the required Appendix J acceptance criteria of 0.75 Lt. Failure of the licensee's procedure (s) to adequately reflect the required Appendix J acceptance criteria is another example of noncompliance (282/85011-018(DRS) against 10 CFR Part 50, Appendix B, Criterion ,

, . _ _- -_ . . __ - _ _ . ___ . _ _ _ _ - -

.

.. .

t

[

(2)'WhenperformingaBN-TOP-1shortdurationtest,the supplemental verification test duration must be approximately  ;

one half the duration of the measured leakage phase of the test and the data reduction technique used for the supplemental test must be the same as described.in the BN-TOP-1 repor i Consistent with the supplemental test duration requirements, ,

procedure SP-1071(8), step 3.15 required the verification test duration be approximately equal to half the integrated. leak  !

rate test duration. The integrated leak rate test-duration was .

22.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> requiring an 11.25 hour2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> verification test, yet, the j verification test was only 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> lur.g with this step of the

'

procedure signed off. Failure by the licensee to follow their  ;

procedures as required by Technical S considered an item of noncompliance (pecification 6.5 is 282/85011-03(DRS)).

'

.As stated above, the data reduction method for the verification  :

'

test must be the same as that used for the measured leakage phase of the test (BN-TOP-1). Contrary to this requirement, .

the licensee used the mass point method of data reduction to t satisfy the verification test acceptance criteria in lieu of the required BN-TOP-1' methodology. When using the BN-TOP-1

,

method to calculate the verification test leakage, the inspector 1

'

found that the BN-TOP-1 leakage was outside of the verification  ;

test acceptance criteria. Failure of the licensee's procedure to i adequately reflect the above requirement is another example of  :

noncompliance (282/85011-01C(DRS))against10CFRPart50, Appendix B, Criterion V.

I

,

(3) 10 CFR Part 50, Appendix J section III.A.3, paragraph b states in part that "the supplemental test method selected shall be  !

l conducted for sufficient duration to establish accurately the L change in leakage' rate between the Type A and supplemental L test." Prior to the test the inspector noted to the licensee

that past Type A supplemental verification test results at

!

Prairie Island had not stabilized within'the acceptance  ; criteria. During the inspector's evaluation of the supplemental- .

I test data, the inspector found that the calculated mass point leakage did not meet the acceptance criteria until late in the l third hour of the test and seemed to be stabilizing in the lower ,

half of the acceptance criteria until the last data point at the t five hour point. This last data soint appeared to the inspector i to indicate a downward trend in tie leakage very similar to past t

tests. The test should have been continued until the change  ;

i~ in leakage rate was accurately established. This failure to i establish a stable supplemental leakage value prior to test l

termination is viewed as poor practice on the part of the

licensee.

c E CILRT Data Evaluation

The inspector evaluated leak rate data to verify the licensee's

calculation of the leak rate. There was acceptable agreement '

t between the inspector's and licensee's leak rate calculations as j  !

t , ,

i

L ,

.- .

indicated in the following summary of mass point results (units are in weight percent per day):

Measurement Licensee Inspector

. Leakage rate calculated 0.0192 0.0192 (Ltm) during CILRT-Ltm at 955 confidence level 0.0239 0.0239 Appendix J Acceptance criteria at 95% confidence level = 0.75 Lt =

0.75 (0.15425) = 0.11569. As indicated above, the adjusted Ltm at the 955. confidence level was less than the Appendix J acceptance criterio Supplemental Test Data Evaluation After completion of the 22.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> test on February 20, 1985, a known leakage of 3.7 scfm or 0.1526 weight percent / day was induced. The inspector evaluated leak rate data to verify the Ifcensee's calculation of the supplemental leak rate. There was acceptable agreement between the inspector's and licensee's leak rate calculations as indicated in the following summary (units are in weight percent per day):

Measurement Licensee Inspector Calculated. leakage (Lc) rate 0.1533 0.1534 during supplemental test Induced leakage rate (Lo) = 0.1526 Appendix J t.cceptance Criterion: Lo+Lta-0.25La<Le<Lo+Ltm+0.25La-(0.13314<Lc<0.21026). As indicated above, the supplemental test results satisfied the requirements of 10 CFR Part 50, Appendix' Summary The licensee attempted to perform a short duration CILRT using the methods described in BN-TOP- Due to procedural and ifcensee staff errors, the results using the BN-T0P-1 method of data reduction were unacceptabl The test, while not running the full 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> that is required for the mass point method of data reduction, ran sufficiently long (22.5' hours) and had sufficiently low leakage to ensure, to the inspector's and Region III's satisfaction, that Prairie Island Unit 1 had an acceptably low containment leakag I No other items of violations or deviations were identifie . Review of Technical Specifications The inspector reviewed the Prairie Island Technical Specifications for

conformance with 10 CFR Part 50, Appendix J requirements and NRC policy regarding-Type A, 8, and C testing. The inspector found the Technical Specifications consistent with current requirement No items of violations or deviations were identifie _ - _ _ - -

-

a

. -.

% Local Leak Rate Results Review ,

I i The inspector reviewed the most recent local leak rate tests-(CLRT's) results

for acceptability. and conforniar.ca with regulatory requirements. The

'

inspector, after reviewing the local results and interviewing licensee

-

personnel found the followingj -

. The licensee performs local ler.k rate / tests with a test rig consisting-of flow meters, a pressure regulator, pressure gauges, tubing and valves. The licensee has the flow meters' calibrated separately from the test rig, then uses them on the test rig, failing to take into account:the pressure drop across the tubing and other components on the rig'resulting from frictio The inspector agreed with the

. licensee that this effect should be negligible at low flow rates, but questions the effect at higher flow rates. This is considered an open item (282/85011-04(DRS)) pending the licensee's resolution of the inspector's concer CFR Part 50, Appendix J, Paragraph III.C.1 and 2 requires the testing of individual containment isolation valves at the calculated peak internal pressure, Pa. Contrary to this requirement, procedures SP-1072-29A, 8 allows the Ifcensee to test their containment soray isolation valves in series, without the quantification of individual valve leakages. At the time of the inspection, the inspector questioned the acceptacility of this testing against the requirements of Appendix J. This information is being forwarded to the office of Nuclear Reacto Regulation and is considered an unresolved item (282/85011-05(DRS))

pending their response.- -

No items of violations or deviations were identifie . As Found Condition of CILRT Results The "as found" condition is.the condition of the containment at the beginning of the outage prior to any repairs or adjustments (ras) to the containment boundary.' 10 CFR 50, Apoendix J, paragraph III.A.1 requires that "During the period between the initiation'of the containment inspec-tion and the performance of the Type A test, no repairs or adjustments shall be made so that the containment can be tested in as close to the

"as is" condition as practical." ANSI N45.4-1972, paragraph 4.2 requires that; "For ratesting, an initial record proof test shall be conducted at time periods and pressures established by the responsible organization, before any preparatory ' repairs'are made. This will disclose the normal state of repair of'the containment structure and a record of the results shall be retained." The NRC's position on the " initial record proof test" requirement, is that it.may be waived, provided the Type A test results are back corrected for all ras to the containment boundary made prior to the performance of the Type A tes If ras are made to the containment boundary prior to the Type A test, local leak rate tests must be performed to determine the leakage rates before and after the ras. The "as found" Type A test results can then be obtained by adding the difference between the affected path leakages before and after ras to the overall Type A test results. These "as s

I

l t ,

, . .

found" leakage rate results are required and carry the same reporting requirements as the other Type A, B and C test results. An acceptable methodology to back correct the Type A test results, as described in paragraph 3.b, of this report, is the minimum pathway leakage methodolog In 1977, as documented in IE Inspection Report Nos. 50-282/77-10 and 50-306/77-06, licensee management was informed of the as found Type A test requiremen It should be noted that in conversations with licensee personnel prior to the performance of the CILRT, the licensee was unaware of the as found Type A test requirements. At the conclusion of this inspection, prior to the exit interview, the inspector noted to the licensee the methodology for obtaining an as found containment leakag Contrary to the 10 CFR Part 50, Appendix J and ANSI N45.4 requirements, the licensee performed repairs prior to the performance of past Type A tests without determining the normal state of repair or the as found

'

condition of containment. This is considered an item of noncompliance (282/85011-06(DRS)).

The inspector reviewed as found and as left local leak rate test results to determine an as found Type A test result. The following is a summary of the as found containment leakage rate (units are in weight percent / day):

Measurement Penalties incurred due to repairs or adjustments prior to the CILRT (corrected for reduced pressure): 0.0254 As Found Type A test results: ,

0.0493

______

TOTAL 0.0747 Appendix J acceptance criteria for the "as found" condition of the containment = 0.75 Lt = 0.11569 wt%/ da No other items of violations or deviations were identifie . Open Items

'

Open items are matters which have been discussed with the licensee, which will be reviewed further by the inspector, and which involve some action on the part of the NRC or licensee or both. Open items disclosed during this inspection are discussed in Paragraphs 3.a and . Unresolved Items

,

Unresolved items are matters about which more information is required in

'

order to ascertain whether they are acceptable items, items of noncompliance, or deviations. An unresolved item disclosed during the inspection is discussed in Paragraph 5.b.

l

L

._

-- - _- -

'

i

.- -

i 10. Exit Interview The inspector met with licensee representatives (denoted in Paragraph 1) at the conclusion of the inspection on May 2,1985 and sumarized the

'

scope and findings of the inspection activities. The licensee acknowledged the inspector's statements. The inspector discussed the likely informational content of the inspection report with regard to documents reviewed by the inspector during the inspection. The licensee

~did not identify any such documents as proprietary. Additional contact with the licensee occurred on May 14, 1985 when the inspector telephone J

the licensee to inform him of a previously identified unresolved item which had, after further review, became an item of noncompliance.

L f

I

\

l

-

i

,

I 9