ML20104A612
| ML20104A612 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 02/23/1979 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20104A616 | List: |
| References | |
| FOIA-84-96 NUDOCS 7904030372 | |
| Download: ML20104A612 (16) | |
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U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION III PRESENTATION OF INVESTIGATION FINDINGS 0F THE 4
SETTLEMENT OF THE DIESEL GENERATOR BUILDING
. AND PIANT AREA FILL CONSUMERS POWER COMPAhT e
MIDLAND NUCLEAR POWER PLANT UNITS 1 AND 2 FEBRUARY 1979 9
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.v' CONTENTS 1.
Scope of Investigation 2.
Identification and Reporting of the Diesel Generator Building Settlement 3.
Review of PSAR/FSAR Commitments 4.
Effects of Ground Water on Plant Area Fill 5.
Compaction Requirements for Plant Area Fill 6.
Noisture Control Requirements for Plant Area Fill
- i. Subgrade Preparation for Plant Area Fill 8.
Nonconformance Reports Identified 9.
Settlement Calculations for Plant Area 10.
Settlement of Administration Building Footings 11.
Interface Between Diesel Generator Building and Electrical Duct Banks t
12.
Soils Placement and Inspection Activities 13.
Inspection Procedures for Plant Fill
- 14.. Final Conclusions l
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Scope of Investigation The NRC Region III office performed an investigation Jo obtain information relating to design and construction actiyities affecting the Diesel Generator Building foundation and plant are'a. fill and the activities involved in the identification and rep'6'rting of the settlement of the building.
The investigation consisted of 240 onsite hours by three NRC inspectors and included examination of pertinen records and proce-dures and interviews with personnel at the Midland Site, the Consumers Power Company offices in Jackson Michigan, and the Bechtel Power Corporation offices in Ann Arbor, Michigan.
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Identification and Reporting of Diesel Generator Building Settlement Inspection Facts
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Bechtel surveyors first noticed unusual settlement on July 22, 1978, while performing routine survey measurements.
The result of the survey with unusual settlement was routinely trans/mittedtoBechtelEngineering. JJ ar,8 77 y
Fleid Project Engineer instructed surveyors to recheck survey and perform survey more frequently. The building was monitored for about one month.
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Apparent settlement continued and when it exceeded the values
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presented in the FSAR, a nonconformance report was prepared on August 18, 1978.
On or abo.ut August 21, 1978, the NRC Resident Inspector was informed of the settlement.
After an exploritory boring program began on August 25, 1978, and preliminary data indicated deficient material, CPQo reported the incident under 10 CFR 50.55(e). m kM 1 ~l
- s. f-0 Fo'rmal notification was made on September 29, 1978.
Conclusion CPCo, after preliminary evaluation of the safety implications, notified the NRC in accordance with 10 CFR 50.55(e).
Finding t
Compliance of 10 CFR 50.55(e), reportability requirements.
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Review of PSAR/FSAR Commitments Inspection Facts
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FSAR Tables 2.5-9 and 2.5-14 identified the typ& of foundation material to be controlled compacted cohesive (c1}ay) fill.
Bechtel Design Drawing C-45 (class 1 fill material areas) specify Zone 2 random fill as any material free of organics with no restrictions on gradation.
FSAR Figure 2.5-48 (estimated ultimates settlements) indicates the Diesel Generator Building to be approximately 3 inches.
FSAR Section 3.8.5.5 (structural acceptance criteria) indicates shallow spread footing foundation settlements to be 1/2 inch or less on compacted fill. The Diesel Generator Building had a shallow spread fpoting foundation.('.)/ C r ~< - ~ /p, - t -,
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The FSAR did not accurately state the design basis or type of a.
fill material supporting class 1 structures.
b.
The FSAR included conflicting values for the settlement of the Diesel Generating Building. founded on spread footing.
Finding Item of noncompliance with 10 CFR 50, Appendix B, Criteri,on III (design control); f ailure to translate design basis as specified in the license application into instructions, procedures or drawings.
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Effect of Ground Water on Plant Area Fil_1_
Inspection Facts PSAR Amendment No. I and Dames and Moore report'oh* foundation investigation indicates a planned drainage system to maintain the ground water level in the plant fill at elevation 603.
PSAR Amendment No. 3 indicates this underdrainage system has been eliminated and the ground water is assumed to rise concurrently with the cooling pond to elevation 625.
Bechtel consultant (Dr. Peck) has indicated that small changes in moisture content of the soil will probably result in increased compressibility.
Conclusion It has not been fully determined whether the full effects of satur-ating the fill was taken into account in the design basis.
Finding Unresolved matter pending licensee evaluation on the effects of permitting the ground water to rise in the plant area fill.
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Compaction Requirements for Plant Area Fill I-Inspection Facts PSAR Amendment No. 3 required the following compiction:
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Clay - 100% of maximum density using a compactive energy of 20,000 f t-lbs (equivalent to 95% of maximum density
,jr using ASTM 1557 Method D with 56,000 ft-lb energy).
Sand - 85% relative density.
Bechtel Specification C-210 requirements:
Clay - 95% of maximum density using ASTM 1557 Method D (same as PSAR)
Sand - 80% relative density (less than PSAR)
Bechtel implemented requirements:
Clay - 95% of maximum using Bechtel Modified Test Method using 20,000 fr-lbs (less than that required by the PSAR and Specification).
Sand - 80% relative density (less than PSAR required but met Specification requirement).
Conclusions s.
Bechtel translated PSAR compaction requirement for clay in construction specification, however, failed to follow requirement.
b.
Bechtel did not translate PSAR compaction requirement for sand to' construction specification.
Finding Item of noncompliance with 10 CFR 50, Appendix B, Criterion V (procedures); failure to implement construction specification requirements.
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Moisture Control Requirements for Plant Area Fill
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Inspection Facts Bechtel Specification C-210 required moisture conditioning in the borrow areas such that the moisture prior to compaction was within plus or minus 2% of optimum moisture content.
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CPCo and Bechtel QA identified that the moisutre control was not being implemented prior to compaction on July 22, 1977.
No association was made with a laboratory compaction standard (i.e., optimum moisture-maximum density curve) was made prior to compaction.
From July 22, 1977, until June 1,1978, Bechtel project engi-neering failed to provide adequate direction for control of moisture content.
Conclusion For all practical purposes, moisture control was not implemented prior to the settlement failure of the Diesel Generator Building.
Finding Item of noncompliance with 10 CFR 50, Ap'pendix B, Criterion XVI (corrective action); failure to take corrective action in a timely manner.
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Subgrade Preparation of Plant Area Fill-Inspection Facts
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PSAR Amendment No. 3 and Dames and Moore foundation investi-sation report indicated that if the construction-schedule required foundation excavation to be left open during the winter that at least 3 1/2 feet of material be excavated before resumption of soils work or that same amount of cover material remain in place to prevent softening of subgrade soils due to frost action.
Bechtel Specification C-210 only prohibited placement of soils frozen surfaces but did not include provision for frost protection of removal prior to resumption.of work.
Correspondence indicates that approximately only 2 inches of frozen / thawed soil was removed prior to resumption of soils work.
- Conclusions a'.
PSAR requirement was not translated into the specification for soils work to preclude placement of soil over subgrade effected by frost action.
b.-
Soil was not protected from frost action nor removed prior to resuming work.-
Finding Item of noncompliance 'sith 10 CFR 50, Appendix B, Criterion III (design control); failure to translate requirements into instuctions or procedures.
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Nonconformance Reports Identified Inspection Facts
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CPCo and Bechtel QA identified repeated nonconforming conditions in the following areas of soils work:
Failing compaction tests due to using incorrect maximum lab density.
Moisture control tolerance.
Inadequate inspection.
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Violation of lift thickness.
Gradation tests not taken.
Gradation requirements not met.
Inadequate test frequency.
i Foremen directing soils not familiar with specification requirements.
r-The most frequently used engineering disposition was to accept "use as is" with or without sound engineering basis.
Conclusion The root of the deficiencies was not adequately corrected to preclude continued degradation of the quality of a safety related activity.
Finding Item of noncompliance with 10 CFR 50, Appendix B, Criterion XVI (corrective action); failure to take adequate corrective action to preclude repetition.
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Settlement Calculations for Plant Area Fill Inspection Facts t
. i Bechtel settlement calculations for the Diesel Generator Building were based on a uniform mat foundation isth a unformily distributed load of intensity of 3000 psf.
FSAR Section 3.8.4.1.2 (Diesel Generator Building) indicates the foundation to be a spread footing type with a load intensity of 4000 psf with independent diesel generator pedestal.
Borated water storage tanks are supported by a circular spread footing. The settlement calculations were based on a uniform circular mat foundation.
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FSAR Table 2.5-16 indicates the soil compressibility parameter to be 0.003 for the soil between elevation 603 and 634. Settle-ment calculations assumed an index of compressibility of 0.001.
Conclusion The estimated settlement values for the Diesel Generator Building and borated water tanks shown in FSAR Figure 2.5-48 were based on conditions that are,pfat variance to existing conditions such as foundation type, load intensity and soil compressibility.
Finding Item of noncompliance with 10 CFR 50, Appendix B, Criterion III (design control); failure to translate design basis as specified in the license application into instructions, procedures or drawings.
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Settlement of Administration Building Footings I-Inspection Facts Administration Building was originally supported. y Zone 2 randem fill material.
Administration building foundation material was tested to the same compaction requirements as class 1 fill.
Administration Building foundation material was placed similar to class 1 fill; by hand held and motorized equipment.
I Bechtel report identified basic cause of administration failure due to the result of repeated erroneous selection of laboratory compaction standard (i.e., incorrect selection of moisture-density standard for soil material being compacted).
Only two borings were authorized to investigate the extent of the deficient soil outside the Administration Building area.
Adminstration failure was then considered to be local condition.
CPCo management- (Corporate Project Engineer and Manager) were not properly informed of the' administration settlement.
Conclusions a.
CPCo did not adequately investigate the extent of the soil deficiency in_the rest of the class 1 fill.
b.
No program changes were-implemented to preclude the continued erroneous selection of the laboratory compaction standard.
Finding
- Item of noncompliance with 10 CFR 50, Appendix B, Criterion XVI (corrective action); failure to take adequate corrective action to L.
identify the extent of the deficiency nor preclude repetition..
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Interface Between Diesel Generator Building and Electrical Duct Banks Inspection Facts Bechtel Electrical Design Drawing E-502 includes a detail to provide separation between the duct banks and diesel generator footing (i.e., styrofoam bond breaker to permit. settlement of the Diesel Generator independent of the duct banks).
Bechtel Construction Drawing C-45 permits the use of random fill Zone 2.
Correspondence from Bechtel engineerng to field (December 27, 1974) permits the use of lean concrete as replacement for Zone 1 and 2 1--
material.
Bechtel field used concrete around electrical duct banks under the diesel generator footings.
Conclusion
' Due to permitting the use of concrete indiscriminate 1y as random fill the uniform settlement of the Diesel Generator Building was restricted in the areas of the duct banks.
Finding Item of noncompliance with 10 CFR 50, Appendix B. Criterion V (procedures); failure to provide adequate instrucitons to Dreclude the use of a material that would cause differential settlement.
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Soils Placement and Inspection Activities Inspection Facts
- a.
Bechtel Design Criteria C-501 requires soils operations to be performed under technical supervision of a qualified soils engineer to verify all materials are placed and compacted in accordance with criteria.
Labor foreman were directing soil operations relative to test locations, test frequency, compaction and moisture.
Bechtel field and QC inspectors were rarely in the areas where soil operations took place.
Accuracy of test locations were a chronic problem.
Moisture was added to the soil after compaction if moisture test failed.
Conclusion Personnel directing the soils operation were not trained in the area of soils work nor were they considered to be qualified soils engineers.
Finding Item of noncompliance with 10 CFR 50, Appendix B, Criterion II (Quality Assurance); failure to provide training to personnel performing safety related activities.
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Inspection Procedures for Plant Fill
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Inspection Facts Bechtel Procedure C-1.02 (compacted backfill) wds written as
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a replacement for Procedures C-210-4 and C-211-1.
Procedure C-1.02 relaxed certain inspection point to surveil-lance only. For example:
Inspection Procedure Activity C-210-4 C-211-1 C-1.02 Material Free of Organics I
S(V)
Material Moisture Conditioned S
I S(V)
Material Not Frozen I
S(V)
Compacted to Density W
S S(V)
Lift Thickness Required W
I S(V)
Conclusions Inspection procedures for soils work were relaxed from original a.
procedural requirements to leaving insufficient mandatory hold points to ascertain backfill materials were installed to requirements.
b.
It was ascertained that surveillance was infrequent and inadequate to verify conformance.
Finding Item of noncompliance with 10 CFR 50, Appendix B, Criterion X (inspection); failure to provide adequate inspection plans.
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Final Conclusions There was inadequate control and supervision of,Iglant fill material placement.
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Corrective action regarding noncomformance related to plant fill was either not taken or was inadequate.
Certain design bases and construction specifications were not followed.
Weaknesses exist in the interface between various components within the construction contractor's organization.
The FSAR contains inconsistent, incorrect and unsupported statements.
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'ls74.i March 12, 1979 FOR E A8 0F HIM0RANDt,H FOR:
R. D. Thornburg, Director, Division of Reactor Construction Inspection Cf fice of Inspection and Esforcasent 4
FRCH:
James C. Esppler. Dtroctor
$UBJECT:
MIDL.AND DIESEL CINERATOR SUI!.DINC AND Pt.Alff arf.A TILL Neetiese se thle esbject were held os February 23, 1979 and March 3,1979 between Consumere Power Coopesy, Sechtel Corporation and NRC. These meet tage were a coet tauettaa of the tavestigatise coeducted by our 1espectore duttag December 11-13. 18-20, 1978 eed Jesuery 4-5, 9-11, 22-23, 1979.
During the Tehruary 23, 1979 neeting we presented to Consume. s i
Power Compsey our preltateery Levest iget tos fladings, e copy of l
which wee previously forwarded to you.
Dertag the nerch 5,1 JF9 eset tag Cassumere Power campeoy prav14.d their respassee to these fledtese, copies of which are secleoed.
Der auseary fledtage with regard to thte metter are se follower 1.
The quality samareece progree for obtaistas proper seit compactles of the Midlead ette was def141eet ta a ember of erose.
2.
Sota of the type esed la the feuedottee of the diesel assereter buildtag to stee located, te verytas degrees. under other close I structures. Wereas escessive sett1smeet has been observed with the diesel generator betidias, the settienest of other Close I strinctures has est neceeded predicted values.
- 3.
Seeerst tecerrect etetseeste are centstead is the FW with toepect to the sell f a.edet toe.
le addittee to these findtage, we have coepiled e itet of techerren geest tees which beer on the re elut toe of this problem. These are emelooed for your vee in working with 3rRS.
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H. L. Thornburg terc'. 1.', 10 1 l
I As previously discussed with you, one of our cercerns le reisted to j
g why construction activities et the MtJ1end e t t e, which could be j
j ef f ected by a Close 1 structure set tiseent shadJ te continued while the total cause of the diesel generator settlement r.e 6 oct yet teen
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d e t e ris tn ed. During the meeting os March' S,19'i, thte question
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wee posed to the licensee. Their response wee that centinuing i
scheduled construction work would not comproutse the ecusaitted evaluet toes or remedtel actions act nahe irrevocable any conditions j
i which do not folly settef y F5AR or 11 cessing requiremente. Bened j
es this, they are w1111eg to oceept the risk of c ontinued i
const ruc t ion.
la that we have queettooed the licensee's 1steet to coettaue construct ion, me cose1Jer that the metter also morreets eneste4tios j
by EQ.
This esenteettee we feel eleo tevelves IIRA for the following reasees:
1.
If one sesees the foundet tee settlement placaneet wee la i
accordance with deelge, them the metter of deelge adequecy becomes questionable.
2.
If ese essees foundettee placaneet did est meet deelge specificettoa.
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S ese suee q.eettoe acceptability ef the se11e candittoo meder tbe j
offacted structures.
It should be pelated out egeta, that the j
type of seile pieced uader the diesel generator bu!! ding were slee j
l t he t ype plac ed ued er o t her C1see 1 ot tw< t ur es eeJ e seoc ia t ed p ipee and w& Litt y 11ees.
3.
Ze 11aht et temes e and b eheve. the metter of esteste deelge slee bessene see of conceru.
4.
Secomme ef ahe licsesee'e total evoluetLee ef ahe specif14 comes for the diesel generator end ptset eres fill settlement to set yet complete. the gweettee of FSAA deelge review eed its esceptab111 y any warrest further etteet tee by MA.
as se alternate appreech to the toewe, rese14eret tee she=14 be gives i
to es NC Digestive or thew Cawee Order which ce=1d eepedite the 11esesee*e eeni1:1eet tee ae t he MC t he t cee 1eeed ceseerwet too will est tempr estee t he deelge f uer t tee o f the involved et tws tur es f or i
t he l if e-t ime of t he p l ee t. It any eles espedite the 11eeeeee's l
1evoet iget tee teen t he bo e te r ow se o f t he d iesel generat e r set t l emoe t eed its relot te en te (or sheenc e) to ot her Cleos i etrima tures.
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~3-March 12,1;;;
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- s fcilowup on this matter and keep you W ne e, g
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Q Directcr
Enclosures:
As stated i
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l MIDI.AND QUESTIONS 1.
The licensee has stated that the fill has settled under its own weight. What assurance is provided that the fill he.s not settled locally under:
a.
Structures with etgid sat foundations as portions of the auxiliary building or service water pump strue; 3.
b.
Class I piping in the fill resulting in lack of continuous support causing additional stress not accounted for in design.
2.
How has the lack of compaction and the increase in soil compressibility affected the seismic response spectra used in design and therefore, the soil-structure interaction during seismic loading?
3.
Af ter current preloading material is removed will additional borings be taken to ascertain that the material has been compacted to the original requirements set forth in the PSAR and construction license application?
4.
Since the foundation material is variable as described in 50.55(e) interia report number 4, how can long tern differential settlement be predicted to assure reliable startup of the D/C in the event of asergency?
5.
What tolerance does the D/C manufacturer req 3 ire on the alignment of the D/C for reliable operation and startup?
6.
Preliminary information indicates that the piping in fill under and in the vicinity of the D/G building have gross deformations l
induced either prior to or during the preload program. What is the estent of the deformation. Is this deformation beyond predictedi i
l If so, what plans are being taken to correct the condition?
7.
The borated water storage tanks and diesel fuel oil tanks have not yet been constructed and are to be located in questionable plant fill of varying quality. Why should those Class I structures be constructed prior to assuring the foundation material is capable of supporting such structures for the plant lif e?
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MIDLAND C'JESTIONS 8.
FSAR Figure 2.5-48 shows estimated ultimate settlementa which indicate a differential settisment across fadividual sat fcundaties and within individual structurer.. Was this differential accounted for in the original design of the est foundatien and in the design of structural member within the structure. If not, what ef fect does this dif ferential settlement have on additional
. stresses induced in the mat or in structure members such as slab-beam-colusa connections?
9.
Based on the information provided in CPCo interia report number 4, it appears that the tests performed on the exploratory borings indicate soil properties that do not meet the original compaction j
criteria set forth in the PSAR and specification for soils work.
What assurance is there that the soil under other Class I structures not ac essible to exploratory boring meet the control compaction requirements!
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UNTIED si ATEs e
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. NUCLE.'.R REGULt. TORY CCf.tMISSICN
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Fce 33, a5 CF I
O 0888CE C8 THE COMM C ONEA i
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. 330sM MD0 TO: Sa-tuel J. Chiik Secretary
%'f FRCM:
Thcmas R. Gibbcii, Legal Assistart L_
j to Cc:missi:ner Bradford SC5 JECT: POSSIBLE EX PARTE CCNTACT IN. :;tA. 0 PROCEQhG, TCKET
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50-329CM A.ND e 50-330CM On July 30. 1980, I had extensive discussions with.*a es G. (e:cter, Director of Seg'en *II, and other Region ::: cersorre; :n gene al 'iPC en'orcetrent issues.
Du*ing tre course of tnese genera' :ts:uss crs, e tasched briefly u:en tne Midland case.
I na ve recer.t'y reviewec f notes of these conversations and have new reali:ed that tne viciana l
conversation could be c:nsidered an ex parte contact..tccordingly,;
j recuest tnat pursuant t: 10 CFR 2.780, yca serve a c::y of tnis e-o and the attached sumary of discussion upon a'l tre :arties in tne wi lano l
l pr:ceeding and also place these docu=ents in tre PCR.
4* t's regare to i
the sunsaary of the discussion, Mr. Kepoler notes that nnile trere arc i
scre technical inaccuracies, the substance of tre Ots:;ssicn is ;: rtrayed correctly.
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Attachrr.ent:
As stated i
I cc: Ja.es G. Kepoler i
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Keppler a;so stated that the C:.-issicners needed to expressence sc.e:ning :s found t
- n one for: or anc:ner the philes:pny :na:
wrong at th e cons ruction size, enstrue:icn will s::p in :nat area antil :he 1:es was resolved.
He gave the exa:p;e cf Midland
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where I&E fcond tha: the diesel generate tuilding nad settled They also f:und tha: :nere was no ;/A progra: ef e x c e ss ive!;..
He related to :he basic foundatica of the site.
any sabstance said the re really wasn' t a O/A program in this area.
In response tae NR issued an order which said tha this should f
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re:edied or work would be s:cpped in 30 days.
theref c re, stayed the order.
Midland torequested a hearing and, is centinu;ng worn today which will make resolatica of the Keppler said that the settlement pection such more dif ficult.
staf f had not yet made up their minds on whether the fix proposed my Midland is acceptanle.
Therefore, the pro:ect continues to He wanted the work stepped
.Se ballt and the p ctiem gets worse.
i antil the protlem is solved.
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