ML18064A390

LER 94-016-00:on 940824,identified Situation Where Previous Concentrated Boric Acid Tank Concentrations Outside of TS Limits.Caused by Inaccurate Analysis.Boric Sample & Analysis Techniques from Pcs & SFP reviewed.W/940923 Ltr

ML18064A390
Person / Time
Site:	Palisades
Issue date:	09/23/1994
From:	Roberts W, Rogers D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-94-016, LER-94-16, NUDOCS 9409300118
Download: ML18064A390 (5)

Text

. ,*

consumers Power David W. Rogers Plant Safety and Licensing Director POWERiNii NllCHlliAN'S PROGRESS

• Palisades Nudear Plant: *27780 Blue Star.Memorial Highway, Covert, Ml 49043 September 23, 1994 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT LICENSEE EVENT. REPORT 94.-016 - INACCURATE ANALYSIS LEADS **ro BORIC ACID .STORAGE..

• TANK. CONCENTRATION BELOW TECHNICAL SPECIFICATION CRITERIA Licen~ee Event Report (LER)94-016 is attached .. This,event:is reportable in

• accordance with 10 CFR 50.73(a)(2)(:i) as a condition prohibited**by*the Palisade~ Technical Specifications.

{l;J(,4J.k~

David WRogers Plant Safety and Licensing Director CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades Attachment

. 9409300118 940923 PDR ACOCK 05000255 A CMS ENEJ?GY COMPANY .

S PDR

NRC Form 366

• 9 U.S. NUCLEAR REGULATORY COMMISSION 19-831 APPROVED OMS NO. 3160-0104 EXPIRES: *a/31/86

• . LICENSEE EVENT REPORT.(LER) .

FACILITY NAME 11 I DOCKET NUMBER 121 PAGE 131 Palisades Plant o. 5 o o o 2 5 5 oF o 4 ---

.TITLE 141 INACCURATE ANALYSIS LEADS TO BORIC ACID STORAGE TANK CONCENTRATION BELOW TECHNICAL SPECIFICATION CRITERIA EVENT DATE (6) LER NUMBER 16) REPORT DATE (6) OTHER FACILITIES INVOLVED (8)

REVISl.ON FAClllTY NAMES MONTH *DAY. YEAR YEAR NUMBER MONTH DAY YEAR N/A 0 . 6 0 0 0 0 8 2 4 9 4 9 4 0 ., 6 00092394 N/A 0 6 0 0 0 THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR I: (C"'1clc ono or man oftJo. followin(IJ (11)

• OPERATINQ N ..,_..,....2_0-.4-02-lb-l-----------..~-2-0-.4-06-lc~)-----------..~,.-60-.7-3-(1)-(2-Hi-vl----------.....-..--7-3.-71-lb-l-------------1 MODE 191 POWER 20.40611111 )(i) 60.36(c)(1) 60.7311H2llvl n.111.:1 20.40611111 )(ii)* 60.361cl121 60.73(1)(2)(viil . OTHER (Specify in Abstract.

20.40611)(1 )(iii) x 60.7311)(2)(i) 60. 7 31all2Hviiil1Al

• below and in Text, 20.40611111 Hivl *so.1311u211;;1 60. 7 3 l1H2HviiillB l NRC Form 366Al 20.40611)(1 JM 60.7 311112)(iiil 60.7311H2llxl

.LICENSEE CONTACT FOR THIS LER 1121 NAME TELEPHONE NUMBER AREA CODE

'WiUiam R. Roberts, Staff Licensing Engineer 6 1 6 7 6 4 8 9 1 3 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED iN THIS REPORT (13f MANUFAC* REPORTABLE MANUFAC* REPORTABLE CAUSE SYSTEM COMPONENr TUR ER . TO NPRDS CAUSE SYSTEM COMPONENT i'LiRER TO NPRDS.

• D C A T K N SUPPLEMENTAL REPORT EXPECTED 1141 MONTH DAY YEAR*

EXPECTED SUBMISSION YES Uf yea, complete EXPECTED SUBMISSION DA TE'J DATE (161 ABS\RACT Uimit to 1400 _.:u, i.e., epproximate/y fifteen ain(lftl-8PllC* typewritten /inesl 1161 On August 24, 1994 with the plant at 100% power, plant personnel identified a situation where previous concentrated boric acid tank concentrations had been*outside of the plant technical .

specification limits. Since present boric acid tank concentrations were .identified as being within

• the technical specification requirements, no immediate actions were required. Reviews of

• previous analysis revealed that, because of sample density and temperatures, relying on a volume sample for the concentrated boric acid tank technical specification concentration verification was

• non-conservative by approximately 10% .. Other chemistry analytical procedures were reviewed to.

determine if they were subject to a similar error due to sample concentration and/or temperature.

No other analysis were determined to be affected. *

• NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION

. (9-83) APPROVED OMB NO. 3160-0104 EXPIRES: B/31/86 LICENSEE EVENT REPORT (LERJTEXT*CONTINUATiON **

FACILITY NAME (1) DOCKET NUMBER (2)* LEf\ NUMBER (3) PAGE (4)

SEQUENTIAL REVISION YEAR' NUMBER NUMBER Palisades Plant 0 5 0 0 *0 2 5 5 9 4 - 0 1 . 6 - 0 . ,0 . OF 0* 4 EVENT DESCRIPTION On August 24, 1994 wi.th the plant at 100% power, plant pe*rsonnel ide.ntified a situatio.n where' previous concentrated boric acid* tank [CA, TK] concentrations had been outside of the plant

• technical specification limits. In the past, the concentration of boric acid in the concentrated boric acid tanks. had been determined by taking a measured volume sample and completing analysis

• based on the volume of the sample taken. After evaluating this technique and recently identifying analysis problems due-to-the techniques µsed for taking the sample volumes, it was decided to * ~-

• revise our analysis methods tq base the sampling on a measured weight sample rather than a ..

measured volume sample. Even though standard laboratory practice fc;>r dilute solutions at room*

temperature is to use pp*m by volume and ppm by weight* interchange'~bly *( 1 ppm = 1 ug/g =

• 1ug/ml), the change in sampling technique to require analysis using a weight basis was determined to be a more technically correct way to analyze for. boron~.

• *.

• In Jun~ of this year a procedyre chan.ge was implemented requiring t~e boric.;acid tar:ik~sample. * * . -

. analysis be analy:zed <?n a weight basis. In Jul,Y~ the r~sults of analysis of th~ boron 1.n ~he J.

concentrated bone acid tank showed that, while meeting the technical spec1f1cat1on limit for boron ,

• concentration; the plant administrative limit* for boron in the tank.-was not met. Puring evaluation of this condition, it was concluded that the step change in*boron concentration was due to the **

• new analysis techniques. In August, in an attempt to quantify the difference in analysis. . .

• methodology for concentrated boric acid solutions, laboratory analysis were performed to measure the experimental difference between the old and new methods. Based on our.analysis ,data, -it

• was estimated that using the previous boron sampling and analysis techniques, boron * . * * * .* .

concentrations were reported approximately 10% high for the concentrated boric. acid*tank . * *.**

samples; **it is estimated that approximately half of this error is due to dehsity effects and halfis due to temperature effects of the volume. .

• _"

• The Palisa-de~ plant technical specificati~ns require that the two concentrnted boric acid tanks to9ether ~hall contain a minimum ~f _118 inch.es of a 6-1 /4 p~rcent to 10 percent by weight bo~ic .

acid solution *at a temperature of at least 25 °F above saturation temperature for the concentration *

• present in the ,tank. *

• Previous boric acid tank analysis resu.lts, beginning in January of 1988 to the. present, were . . * .

reviewed and it was determined that on March 18, 1991 both the A and the B concentrated boric*

acid tanks did not have the minimum amount of _boron required by- the technical specifications.*

The A tank's corrected concentration was 10,677 ppmB and the B tank's corrected concentration .

.was 10,534 ppmB. The Technical Specification minimum of 6-1/4 weight percent .e_quals.J0;928 ..

ppmB. . * .* . . . . . .. . * . .

. . . ~ .

The review of past results also showed that: on November 29, 1993, the B boric acid storage tank did not have the minimum amount of boron required by the technical specifications. The B tank's

• corrected concentration was 10, 760 ppmB compared to the Technical Specification minimum of

• 10,928 ppmB. . .

This event is reportable in accordance with 10 CFR 50. 73(a)2(i) as. a condition prohibited by *the Palisades Technical Specifications.

~:.

. NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION (9-831- .. APPROVED OMB NO. 3160-0104

. :.. -_* *: EXPIRES:.:il/31186. *

.. LICENSEE EVENT REPORT (LERI .TEXT CONTINUATION. * . .** ;.

FACILITY NAME (11 DOCKET NUM.BER 121 LER NUMBER 131 PAGE 141 SEQUENTIAL REVISION YEAR NUMBER NUMBER Palisades Plant 0 5 0 0 Q 2 5 5 9 4 - 0 1 6 - 0 0 0 3 . OF 0 4 .

CAUSE OF THE EVENT . .

The root cause of the ,event was the failure of our previous analysis techniques to consider the affects that concentration and temperature have on the analysis of boron in concentrated boric*

acid solutions. * *

• ANALYSIS OF THE EVENT

. Previous to the boron analysis method change in June of 1994, sample aliquot were measured by*

volume for boron analysis. The procedure change in June required sample aliquot to be measure.d by weight. Previously, the procedure assumed the wei£ht and the volume analysis methods . .

• • would be equivalent. This is true for pure water at 4°C, as one milliliter of pure water weighs one :

~ram. As. solutions in. wa~e.r. become more and more conce~tra.t~d~ the. difference ~etweeh mass **

m grams and volume m m1ll1llters becomes more and more s1gnif1cant. In the technical . * *

• specification requir~d range for the boric acid storage tanks, 10,928 ppm boron to 17,484 ppm boron, this difference.amounts to between 3.24% and 5.14%. This results,in.one .. rililliliter~of .

10,928 ppm Boron solution weighing 1.0324 grams, and one milliliter of 17,484 ppm boron * * .

solution weighing 1.0514 grams, The sample aliquot, whether measured by weight or'volume, is* : ">

. *used in the denominator to calculate the boron concentration.* This would account for between . . *

• 3.24% and 5.14% difference between weight and volume measurements when determining bor.ic ...

• acid concentrations. * . * . .* . . * * * * . * * . * ** .

• The boric a.cid' solution in the boric acid storage tanks is heated in order to. maintain the r~q-uir~d

• boric acid concentrations in solution. Samples analyzed .from these two tanks have to* be kept hot in order.to keep the.boric acid_ in solution' during sample delivery for*~malysis~ Measurements .. ot. ,:.

temperature made on boric acid storage tanks after sampling ~ave shown that th~y range

• between 55°C and q5°C. These cire the .temperatures.at which the eppendorf p1pet must .

• accurately deliver its volu.me. *Testing of these pipets to determine their ability to deliver the*.

specified volume at these temperatures have _re.vealed that they deliver approximately five percent more volume than specified. This five percent error is. in addition.to the previous error determined.

due solely to the* difference between mass and volume. The total of these two errors results jn

. approximately a 8.24% to 10.14% total error for boron analysis of these tanks. . . * *

• In .order to determine if this error significantly affected other boron analysis in plant *systems, *

• temperature and density effects on other plant analysis were. considered. All other boron samples of plant systems are of a low enough concentration of boric acid that the boron remains in solution at room temperature. These.samples, wheri analyzed by volume delivery, were able to be .

delivered at the 'pipet calibration temperature of 25°C. - . . ** *. . . *. *.

The second factor to be considered is .the density of the. boric acid solutions in other pla~t systems. The difference between mass and .volume for a boric acid solution containing 3496 ppm .

boron would amount to 0.69% difference. One milliliter of 3496 ppni boron would weigh .

-1.0069 grams. *As boric acid solution concentrations decrease* from 3496 ppm, the difference* .*:

between mass a~d vo.lume decrease, approaching zero .. Since no plant systems, other than:the concentrated bone acid system, should ever have contained more than 3496 ppm boron, the. *.

largest error possible between weight and volume would be less than 0.69% .. * * .*

NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION

.. (9*831 APPROVED OMB NO. 3160-0104 EXPIRES: .B/31/86 LICENSEE EVENT.REPORT (LERI TEXT CONTINUATION FACILITY NAME {11 DOCKET NUMBER 121 LER NUMBER 131

• PAGE {4)

SEQUENTIAL REVISION.

YEAR NUMBER NUMBER Palisades Plant o s o* o o 2 s* s s 4 -** o 6 - Q Q Q 4 OF Q 4 SAFETY SIGNIFICANCE In late 1990, an investiQation was completed for the Palisades plant to determine the need for .

con~e~trate~ boric acid miection .through the charging pump~ to mitigate any potential. accid~nt beginning with fuel cycle 9. During these events, the charQing pumps would take their suction from the concentrated boric acid tanks. The results of the investigation showed no Palisades accident analysis requires the use of the charging eumps to provide reactivity control. Two FSAR analyzed events, "Steam Generator Tube Rupture,' and "Radiological Consequences of Failure Of Small Lines Carrying Primary Coolant Outside Containment," take*credit for the charging pumps.

Both of these analysis use the char~ing pumps for inventory control, not reactivity control. *The *.;

• investigation concluded that reductions in the boric acid concentration of the concentrated boric acid tanks would not impact any of the analyzed plant accidents. The -analysis also referenced several other plants who had come to the same analysis conclusions and had taken the addition~!

step of reducing their boric acid tank concentrations.

• Therefore, there is no safety impact for the concentration in the concentrated boric acid_*tanks

• not meeting the technical specification acceptance criteria. . . * * . * .

CORRECTIVE ACTION The boron sample and analysis techniques fro~ the primary coolant s'ystem and the spent fuel

• pool were reviewed to determine if -our recent findings have any bearing on their analysis re~ults.

These samples are much le.ss concentrated and are analyzed at lower temperatures.such that the density and temperature defects noted in the old analysis methods* associated with:the .. -')'

concentrated boric acid tanks do not exist when these samples are analyzed.

• A.review was performed of other analytical procedures which may be subject to a similar error due to sample concentration and or temperature. No other analyses were identified as being .

• affected. *

• No other additional .corrective actions are proposed as the current method for performing boron * *.

analysis by weight, is the most accurate ana_lysis. * *. . * *. . * *. *..

ADDITIONAL INFORMATION None ..

. . . . -