ML20125B500
| ML20125B500 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 07/15/1982 |
| From: | Abramson L, Lurie D NRC OFFICE OF RESOURCE MANAGEMENT (ORM) |
| To: | Clark J NRC OFFICE OF RESOURCE MANAGEMENT (ORM) |
| Shared Package | |
| ML20125B272 | List: |
| References | |
| FOIA-84-893 NUDOCS 8506110433 | |
| Download: ML20125B500 (4) | |
Text
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go areg(o, UNITED STATES 4
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,o NUCLE AR REGULATORY COMMISSION I
wasHINGTow, p. c. rossa JUL 151942 MEMORANDUM FOR:
John W. Clark, Chief Management Analysis Branch Office of Resource Management FROM:
lee Abramson, MAB Dan Lurie, MAB i
SUBJECT:
TRIP TO MIDLAND NUCLEAR STATION, JUNE 30 - JULY 1,1982 AttherequestofW.S.Little(RegionIII),peramemotoyoudatedJune8, we met with F. Hawkins, Region III Inspector, and Consumers Power (CP) and Bechtel staff at Midland on June 30 - July 1 to discuss the testing of potentially defective containment coatings in Units 1 and 2.
According to the technical specifications, the interior of the containment is to be covered with a coating which can be decontaminated in the event of an accident.
This coating is placed on top of a sealant coating which is applied directly to the concrete.
In order to provide a better base for the outer coating, the workmen applied two coats of the sealant.
- However, a CP engineer has discovered that, for reasons not completely understood, l
the two coats of scalant did not always adhere to each other.
Tnis delami-nation phenomenon is a potential problem because, if the containment spray system is activated, the intake to the sump pump could become clogged if enough of the coating flakes off.
To determine the extent of the delamination, CP divided the inside of gach containment into 50010' x 10' test areas and examined a small section near the center of each test area.
On the basis of this examination, CP has removed the original coating and recoated about half of Unit I and over 80 percent of Unit 2.
The remaining areas of Units 1 and 2 showed no defects in the initial examination.
In order to demonstrate that the delamination phenomenon does not present a potential problem for the areas of Units 1 and 2 which have not been recoated, CP believes that it is sufficient to show that, with 95 percent assurance, no more than 5 percent of the unre-coated areas in eac1 of Units 1 and 2 could delaminate.
(This is referred toasthe95/95 criterion.) CP has divided each containment interior into eight sections and intends to apply the 95/95 criterion separately to each of the eight sections, provided the section was not previously completely recoated.
The sampling plan adopted by CP was to be conducted in at most three stages, according to the enclosed attachment. Each stage requires testing of a predetermined number of areas for delamination.
The test areas, selected g6d1dll-m 433 841229 pg avTo m
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John W. Clark
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JUL 151982 l
at random, are 2' x 2', and almost all of the sampling required by the plan has already been carried out. The three-stage plan, however, does not satisfy the 95/95 criterion, as claimed by Bechtel. After considerable l
discussion, we were able to convince CP/Bechtel that their three-stage l
plan provides only 91 percent assurance that at most 5 percent of the area I
of the tested section could delaminate.
Even though this finding invalidates the sampling plan, as pro >osed, we were able to show CP how to achieve the 95/95 criterion with tie tests which have already been cairied out. We pointed out that, since only one sump pump serves the entire containment, it is sufficient to achieve the 95/95 criterion for the containment as a whole, instead of separately for each of the eight sections into which each containment was divided.
In order to avoid possible statistical pitfalls associated with multi-state plans, we suggested that CP use only the results of the first 59 tests (the first stage) for each section.
For Unit 1, 8 x 59 = 472 tests will have been carried out, and for Unit 2, 4 x 59 = 236 tests will have been carried out (four of the eight sections in Unit 2 have already been completely re-coated).
In view of these large sample sizes, and based on the tests carried out so far, it is virtually certain that the 95/95 criterion will be satisfied for each containment.
Our suggested approach was accepted by CP, although they intend to continue with a more conservative plan. Accordino to that plan. CP will test 59 areas in each section and replaci me coot < nu for the entire tection if l
TUTn A_sino m aren shows delamination.
hts plan, clearly, would more than I
satisfy the 95/95 criterion adopted by CP, provided that the total number of defective areas is less than the threshold required by our-suggested c single-stage plan.
We also made the point that a 95/95 criterion is not as informative as a one-sided 95 percent confidence interval for the proportion of defectives (delaminated areas) in the population.
This interval would be easier to interpret than the present 95/95 criterion.
1 Finally, we questioned the 95 percent assurance criterion as being too low, since this allows for the )ossibility that the containment spray system may fail to operate with a pro > ability as hi9h as 5 percent.
Because it seemed i
to us that this probability is considerably larger than the engineered un-l reliability of tie containment spray system, we suggested that CP show that the increased unreliability due to the delamination phenomenon does not significantly increase the total unreliability of the containment spray system. CP agreed that this is a reasonable requirement and will address it in their report.
- h MA K
Lee Abramson Dan Lurie i
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John W. Clark.
3 JUL 151982 a
l Enclosure cc:
C. Williams. Region III E. Triner, RN/B l
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.'[,,,, 'g UNITED STATES
/
NUCLEAR REGULATORY COMMISSION o
{
I MEGION lli e,
?os MoolrvtLT MoAo C LEN I LLYN. BL LINots 60137 1118. 7. 8 1 % 2 '
Docket No. 50-329 f
i Docket No. 50-330 l
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s Consumers Power Company A1TN:
Mr. James W. Cook Vice President Midland Project 1
1945 West Parnall Road Jackson, MI 49201 Gentlemen l
This refers to the routino safety inspection conducted by Mr. F. C. llawkins of this of fice on June 2 4, 30 and July 1,1982, and Hessrs. L. Abramson and D. Lurie of the NRC office of Resource Management on June 30 and July 1, 1982, of activities at Midland Nuclear power Plant Unita 1 and 2, authorized by NRC Construction Permits No. CIPR 81 and No. CPPR-82 and to the discussion of our findings with Mr. M. L. Curland and others of your staf f at the conclusion of the inspection.
The enclosed copy of our inspeiction repo-t identifica areas examined during j
the inspection. Within these arcas, the inspection consisted of a selective i
examination of procedures and representative records, observations, and in-torviews with personnel.
No items of noncompliante with NRC requirements were identified during the course of this inspectier;.
In accordance with l'0 CTR 2.790 of the Commission's regulations, a copy of this letter and the enclosed inspection report will be pinced in the NRC's Public Document Room.
If this toport contains al.y information that you (or your t.ontractors) believe to be exempt from dinclosure under 10 CTH 9.5(a)(4), it is necessary that you (a) notify this office by tele-phone within ten (10) days f rom the date of this letter of your intention to file a request for withholdings and (b) submit within twenty five (20) days f rom the date of this letter a written application to this of fice to withhold such information.
If your receipt of this Intter has been l
e
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i Consumers Power Company 2
JUL 2 8 082 delayed such that less than seven (7) days are available for your review, please notify this office promptly so that a new due date may be estab-lished.
Consistent with Section 2.790(b)(1), any such application must L
be accompanied by an affidavit executed by the owner of the information l
which identifies the document or part souaht to be withheld, and which contains a full statement of the reasons which are the bases for the claim that the information should be withheld from public disclosure, This section further requires the statement to address with specificity i
the considerations listed in 10 CFR 2.790(b)(4). The information nought co be withheld shell be incorporated as far as possible into a separate part of the affidavit.
If we do not hear from you in this regard within
.the specified periods noted above, a copy of this letter and the enclosed inspection report will be placed in the Public Document Room.
We will gladly discuss any questions you have concerning this inspection.
Sincerely, h
W. S. Little, Chief Engineering Inspection Branch Enclosure Inspection Reports t
No. 50 329/82 10(DLTP) and i
No. 50 330/82 10(DETP) cc w/encli D:lB/ Document Control Desk (RIDS)
Resident inspector, RI!!
l The Honorable Charles hechhoofer, ASLB Th Honorable Jerry liarbour, ASLB l
The Honorable Traderick P. Cowan, ASLB The Honorable Ralph 5. Decker, ASLB i
Michael Miller I
Ronald Callen, Michif,an Public Service Commission Hyron H. Cherry Barbara Stamirls Mary Sinclair Wendell Harshall l
Colonel Steve J. Gadler (P.E.)
N r$s 50 "4 ep yytte l
HakM/sv Abram=on Lurie Boyd Williams Li 7/21/82 4
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U.S. NUCLEAR REGULATORY COMMISSION l
REGION III Reports No. 50-329/82-10(DETP); 50-330/82-10(DETP) g i
l Docket Nos. 50-329; 50-330 Licenses No. CPPR-81; CPPR-82 Licensee: Consumers Power Company 1945 West Parnall Road Jackson, MI 49201 Facility Names Hidland Nuclear Power Plant, Units 1 and 2
' Inspection Att Hidland Site, Hidland, MI Inspections Conducted: June 2 4, 30 and July 1, 1982 7[EI-[jd.
Inspector F. C. Hawkins Accornpanying Personnel:
L. Abramson (June 30 and July 1, 1982)
D. Lurie (June 30 and July 1, 1982) h
.a A; proved By:
L. C. Williat!
Chief If LI 1
Plant Systems Section
~j l
jnerect ton Sumary g
luset ton on Juna : 'i 30 and Jul li.lH;_U3rorts no. So 3;3g210lnqPJu t
10.)30 /.6,t2MDI.Ty])
bic_n.s lpjpec t e_d i Followup on reported 50.55(e) item regarding Unita 1 and 2 containment internal structures coating deficiency. The inspect ion involved a total of 58 inspector hours onsite by one Region 111 inspector and two representatives f rom the Of fice of Resource Hanagement.
Ecoults No items of noncernpliance or devlations were identifled.
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DETAll5 l
l 1.
Persons Centacted Consusers Power Coepany (CPCo) l
- tt. Curland, Site Quelity Assurance Superintendent
- M. Puschel, Staff Eng4ncer
- B. Palmer, Resident Site Reeedial Soils Supervisor l
- A. Tselepis, Coatings Specialist techtel Pc er Corporation
- T. Murphy, Trchitect/ Planning i
- V.
Iands, Eesident Architect
- R. Carlint, Coatings Specialist
- L. Snyder, Resident Quality Engineer
- P. Hateh, Reliability Engineer I
- E. D.atton, Civil Quality Centrol Engineer l
Other R. Cock, Ecsident Inspector
- Denotes those attending the exit interview.
2.
Tunctienal or Progra-Areas inspected This inspectier was conducted te assess the acceptability and status of corre;tive actiens taken by Ccest-ers Tc.or Cearany with regard to the identified Unit 1 and 2 c.cntaiteent internal structures coating deficiencies. The inspection on June 2 4, 1982 focused on:
(1) dis-cussien of investigations to identify the cause of the identified costir;g deficiencies, (2) discussion of the Unit 1 and 2 reactor building espring/ testing progras, (3) review of CBA environmental test results, (4) review of pertainent Bechtel cesting specificaticns, subcer. tractor procedures and quality records, and (5) observation cf inprn:ess coatings removal. The June 30 and July 1. 1982 inspectica ef fort 1,as directed tward the assestsent of Censueer Fo.or Ceepany's statistical af proach to the testing of the potentially defectise c oa t irigs.
In 1979, a Cor surers Nor Ceepany representatise identified a loss of adhesion between successive c, oats of the Systes 9 teating in the Unit 2 reactor building. As a result, Management Corttetive Action Report (WAR) No. 35 was written on Noveeter 13, 1979, to properly identify the deficiency and assure its preter disposition.
The identified loss of adhesten between successive ceats of Systee 9 had the potential to allev paint natorial to be carriet into the cen-taintent suar as a rebult of a reactor accident fol b ed by snitiatien of the cw.tainment spray systee. This scenario of cen.atnnent coatings 3
i 9.
i l
failure represented the potential to exceed the allowable 50% blockage of the inner surp screen (reference NRC Regulatory Guide 1.82k In i
r Consumers Power Company's estimation, the delamination represented a l
significant construction deficiency and was therefore reportable per l
10 CTR 50.55(e).
[
The System 9 coating is a decontaminable system which was applied to approximately 50,000 square feet in each containment. The ideal three coat System 9 consisted of one coat of Ameron Nu-Klad 117 filler /
surfacer and two coats of Ameron Amercoat 90 topcoat. Nu Klad 117 is an epoxy coating used to fill and seal the concrete surface.
Amercoat 90 is a modified phenolic epoxy coating which provides the decontaminable finish coat. Ameron's technical data sheet allows a i
second coat of Nu-Klad 117, as required to fill and seal the concrete I
surface. The majority of completed System 9 coatings at Midland consists of two coats of Nu-Klad'117 and two costs of Amercoat 90.
To establish the extent of the delamination, the completed System 9 coatings in the Unit 1 and 2 reactor buildings were subdivided into 100 square foot grids and knife adhesion tests were performed on each i
grid. The results of this testing indicated that approximately 5% of Unit 1 and 18'. of the Unit 2 System 9 coating exhibited inadequate t
intercoat adhesion between the two coats of Nu Klad 117.
Concurrent with these activities, conting samples from completed field work were taken in accordance with Bechtel Specification A 55.
The samples were taken from areas which were known to pass the knife
[
adhesion test and tested at simulated design basis accident (DBA) conditions in accordance with Bechtel Specification A 45, ANSI N101.2 1972 and ANSI N5.12 1974. The intent of the program was i
to correlate the results of the DBA coating performance tests with the results of the knife cdhesion test method.
Limited testing was also performed to establish correlation between the E1cometer 106 Adhesion Tester and the knife adhnston test method. The combination of the results from these two test programs clearly establish the validity of the knife adhesion test for determining the acceptability of the System 9 coatings.
f Additionally, Consumers Power Company and several independent i
laboratories conducted extensive investigations into the Ameron product and those application variables with potential effect on j
the performance of the System 9 coating.
The variables which were evaluated included (1) batch and mixing variations, (2) addition of solvent, (3) surface and intercoat contamination, (4) relative humidity and temperature, (5) application variables, and (6) pack-aging variables. The results of these investigations identified several factors which could singly, or in combination with other i
l factors, cause the observed loss of adhesion between successive i
coats of Nu Klad 117. They are as follows:
Variations of relative humidity and temperature during application and curing.
3
s.
l Addition of Amercoat 6 thinner to the batch to extend the apparent pot life.
l Application of Nu-Klad 117 near or after the end of the effective
l pot lite.
Time between application of successive Nu-Klad 117 coats.
Based on the results of the knife adhesion tests, which were performed i
on each 10 square foot grid, coatings which failed the test were removed. Bechtel Speciffeations A-56, which governs the removal and repair of defective System 9 coatings, was reviewed. A-56 contained l
the appropriate provisions to control the work activities.
Bechtel Specification A-57, which contains provisions for the prepara-tion and testing of panels to qualify the various coating repair systems, l
was also reviewed. Samples from the panels were tested at simulated DBA conditions and the results of the tests were reviewed. The test results clearly qualified the coating systems as Service Level I as defined by I
ANSI N5.12 1974 It is our conclusion that the controls and tests required by Specifications A-56 and A-57 are adequate to prevent recurrence of the coating deficiency.
In order to qualify the unremoved Syste.m 9 coatings, the remaining coatings are being tested against a 95/95 statistical criterion. This l
criterion provides that with 95 percent assurance, no more than five percent of the unremoved coatings in each contain+nent will delaminate.
l To implement the 95/95 criterion, Consumers power Company divided each i
containment into eight noctions and subdivided each section into two l
foot by two foot grids. The sanpling plan adopted by Consumers Power requires that 59 grids in each section be tested. Further, should a single grid fall the knife adhesion test, the coatings in the entire section will be removed.
It is our view that this plan will more than natisfy the 95/95 criterion adopted by Consumers Power.
The testing program is currently in progress at the flidland site, i
hicensee personnel stated that completion was tentatively scheduled for October 1, 1982. Agreement was rent.hed during this inspection that Consumers Power Conpany would submit a final report on the resolution l
of this 50.55(e) item upon completion of the testing program and removal I
of all defective coatings, final acceptance is pending the lamuance of the Final report and its subsequent review by the NHC.
3.
fxit I nt eirv i ew The Region !!! inspectors met with licenses representatives at the conclusion of the inspection. The results of the inspection were numenarized during the exit intervlaw.
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