ML20137F920

TS Change Request NPF-38-191 to License NPF-38,modifying TS Surveillance Requirements 4.5.2.d.3 & 4.5.2.d.4 Re Granular Trisodium Phosphate Dodecahydrate

ML20137F920
Person / Time
Site:	Waterford
Issue date:	03/27/1997
From:	Dugger C ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20137F924	List: ML20137F920 ML20137F979
References
W3F1-97-0053, W3F1-97-53, NUDOCS 9704010269
Download: ML20137F920 (10)

Text

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Enttrgy Operations, Inc.

i Kihona, LA 700fE>-0751 Tel 504 739 6600 Charles M. Dugger vc P es c mt. opwaws W3F1-97-0053 A4.05 PR March 27,1997 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555

Subject:

Waterford 3 SES Docket No. 50-382 License No. NPF-38 Technical Specification Change Request NPF-38-191 Gentlemen:

The attached description and safety analysis support a change to the Waterford 3 Technical Specifications (TS). The proposed change modifies TS surveillance -

requirements 4.5.2.d.3 and 4.5.2.d.4. The proposed change specifies granular I trisodium phosphate dodecahydrate (TSP), increases the minimum required amount of TSP that is maintained in containment during power operation, and adjusts the TSP sampling requirement accordingly. A change to the Technical Specification Basis 3/4.5.2 has been included to support this change. ,

l This proposed change has been evaluated in accordance with 10CFR50.91(a)(1),

using the criteria in 10CFR50.92(c), and it has been determined that this request involves no significant hazards consideration.

The circumstances surrounding this change do not meet the NRC's criteria for exigent or emergency review. However, because of the significant impact on plant  ;

operations, we respectfully request an expeditious review. Entergy Operations  ;

requests the effective date for this change coincide with the completion of RFO8.

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Technical Specification Change Request NPF-38-191 W3F1-97-0053 Page 2 March 27,1997 Please note that Technical Specification Change Request NPF-38-192 also requesting changes to Technical Specification 3/4.5.2 and its bases has been submitted under separate letter, W3F1-97-0054.

i Should you have any questions or comments concerning this request, please contact P.L. Caropino at (504) 739-6692.

Very truly yours,

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p t1 C.M. Dugger Vice President, Operations Waterford 3 CMD/DBM/ssf

Attachment:

Affidavit NPF-38-191 cc: E.W. Merschoff, NRC Region IV C.P. Patel, NRC-NRR R.B. McGehee  ;

N.S. Reynolds NRC Resident Inspectors Office Administrator Radiation Protection Division (State of Louisiana)

American Nuclear Insurers

, UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION 4

' In the matter of )

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4 Entergy Operations, incorporated ) Docket No. 50-382 Waterford 3 Steam Electric Station )

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W AFFIDAVIT

{ Charles Marshall Dugger, being duly sworn, hereby deposes and says that he is Vice l President Operations - Waterford 3 of Entergy Operations, incorporated; that he is duly authorized to sign and file with the Nuclear Regulatory Commission the attached I

Technical fgecification Change Request NPF-38-191; that he is familiar with the

' content thereof; and that the matters set forth therein are true and correct to the best of his knowledge, information and belief.

) /9 ) l J' I w I uw Charles Marshall Dugger dh Vice President Operations - Waterford 3 STATE OF LOUISlANA )

) ss PARISH OF ST. CHARLES )

Subscribed and sworn to before me, a Notary Public in and for the Parish and State above named this 2*1* day of M Ac e H ,1997,

- K/t ? , 5 tiotary Public My Commission expires w . r u _ e r r_ ,

l i DESCRIPTION AND SAFETY ANALYSIS

, OF PROPOSED CHANGE NPF-38-191 l - This submittal proposes to increase the amount of trisodium phosphate dodecahydrate

! (TSP) verified in surveillance requirement 4.5.2.d.3 from the current value of 97.5 cubic ,

- feet to 380 cubic feet. Changes the word solid to granular to more accurately describe l

! the TSP used. The representative TSP sample size in surveillance requirement

j. 4.5.2.d.4 will be increased from 410.01 grams to 13.0710.03 grams for the same 4 liters of solution. Surveillance requirement 4.5.2.d.4 is also changed to specify that the j test solution be borated to 3011 ppm boron to be representative of calculated post-

LOCA sump conditions. This change is modeled on recently approved Technical l Specification (TS) amendments for Fod Calhoun and Calvert Cliffs.

l Existina Specification See Attachment A Proposed Specification See Attachment B Backaround Design Change (DC) 3491 will increase the storage capacity for TSP in containment.

The increased storage capacity anticipates future increases in the boron I concentrations because of longer fuel cycles and the corresponding higher energy fuel l designs. DC-3491 has been evaluated under 10CFR50.59 and found not to involve an unreviewed safety question.

During the preparation of DC-3491, the original design calculation for determining the current quantity of TSP could not be reproduced. Analysis, using the original assumptions, based on recent calculation methods indicate that more TSP than that originally calculated is needed to neutralize the expected amount of boric acid solution in the limiting design basis event. Laboratory tests using a solution of 2300 ppm boron resulted in a pH of 6.97. Note that ANSI /ANS 56.5-1979 "PWR & BWR Containment Design Criteria" section 7.3.5 states, "Beyond 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> sump pH shall be maintained between 6.5 and 9.5 for material compatibility." An operability evaluation was performed that determined that the existing amount of TSP will neutralize the safety injection sump to a pH of equal to or greater than 7.0 for the existing boric acid concentrations and therefore the current amounts of TSP in containment do not 4

represent a condition adverse to safety for the remainder of Cycle 8. Based on the results of this evaluation, Waterford 3 established administrative controls to ensure that the maximum boric acid concentration expected in a design bases accident (DBA) will l not exceed the neutralizing ability of the TSP currently in containment. This event is

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E similar to an event which occurred at Fort Calhoun in late 1995 (reference Fort Calhoun (Docket No. 50-285) Licensing Event Report 95-08).

i- Description l This submittsi requests a change to TS surveillance requirements 4.5.2.d.3 and  ;

4.5.2.d.4. The proposed change more accurately describes the TSP used and .:

increases the minimum required amount of TSP that is maintained in containment i during powei operation. The proposed change also increases the TSP sample size to )

correspond with the increase in TSP as well as specifying a test solution boron concentration representative of post-LOCA sump conditions.  ;

I Following a LOCA, the Containment Spray System activates to limit the containment

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atmosphere pressure and temperature increase and to thereby reduce the amount of -

airborne radioactivity leakage to the outside environment. The containment spray pumps discharge borated water from the Refueling Water Storage Pool (RWSP) to the_ l spray headers end nozzles located near the top of the containment. The water j introduced into the containment in this manner will be mixed in the safety injection sump with the water from the Reactor Coolant System (RCS). The resultant mixture will be recire Wed to the spray system only after the inventory of the RWSP is nearly depleted. When the level in the RWSP reaches the point where the Recirculation t Actuation Signal (RAS) setpoint has been reached, the High Pressure Safety injection l and. Containment Spray pump suctions change froin the RWSP to the safety injection I sump. l Granular TSP is stored in the containment lower level to raise the pH of the water  !

following a LOCA to greater than or equal to 7.0. The TSP is stored in stainless steel  ;

baskets with mesh screen sides near the Safety injection sump. As the pH of the water  !

increases, more radioactive iodine is kept in solution and the amount of airborne radioactive leakage is decreased. This also lessens the potential for boric acid solution reacting with galvanized metal in containment to release hydrogen. An additional advantage of a higher pH is the beneficial reduction in chloride stress corrosion cracking of metal components in the containment following an accident. Branch Technical Position MTEB 6-1 entitled, "pH For Emergency Coolant Water For PWRs" recommends a minimum pH of 7.0 to reduce chloride stress corrosion cracking of those ,

components. )

l Borated water from the containment spray and the LOCA will dissolve the TSP and thus raise the pH of the solution. The chemistry of liquid compartments in containment will be different depending on the exact nature of the DBA. A large LOCA will empty most of the RCS into containment before safety injection or containment spray can start. An end of cycle DBA could put relatively low concentration solution into the bottom of containment. Higher concentration solution would finish filling containment up to the 2

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point of RAS. In a small break LOCA, the opposite happens, i.e., the high

] concentration solution fills containment first.

l The TSP baskets are near the safety injection sump where the ECCS pumps take suction after RAS. The safety injection sump is at a higher grade level than the bottom of the reactor cavity and containment sump. Mixing is achieved as the solution is continuously recirculated from the Si sump to the spray nozzles. Water in the reactor cavity circulates as a result of thermal currents set up by the reactor vessel. The water i

flowing through the TSP baskets and going into the safety injection suction pipe will l dissolve the TSP within three hours following Containment Spray Actuation Signal. l Approximately one-fourth of the TSP will be dissolved during the injection mode. The TSP baskets are so located that all sprayed water dissolving the TSP will drain to the l safety injection sump. j This submittal proposes to increase the amount of TSP verified in surveillance requirement 4.5.2.d.3 from the current value of 97.5 cubic feet to 380 cubic feet. ,

Changes the word solid to granular to more accurately describe the TSP used.

Increases the representative TSP sample size in surveillance requirement 4.5.2.d.4 from 410.01 grams to 13.0710.03 grams for the same 410.1 liters of solution. The

increase in the delta from 0.01 to 0.03 maintains the currently allowed 0.25% delta.

Surveiliance requirement 4.5.2.d.4 is also changed to specify that the test solution be borated to 3011 ppm boron to be representative of post-LOCA sump conditions. This increase in TSP to 380 cubic feet will bound all post-LOCA sump boron concentrations up to a maximum of 3011 ppm boron. This maximum boron concentration of 3011 ppm boron is calculated to be the highest post-LOCA sump boron concentration expected )

based on anticipated increases in boron concentrations required to support longer fuel cycles and higher energy fuel designs.

Safety Analysis The proposed change described above shall be deemed to involve a significant hazards consideration if there is e positive finding in any of the following areas:

1. Will operation of the facility in accordance with this proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No Granular trisodium phosphate dodecahydrate is stored in the containment lower level to raise the pH of the water following a LOCA. As the pH of the water increases, more radioactive iodine is kept in solution and the amount of i airborne radioactive leakage is decreased. This also lessens the potential for boric acid solution reacting with galvanized metal in containment to release 3

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hydrogen. ' An additional advantage of a higher pH is the beneficial reduction in  !'

} chloride stress corrosion cracking of metal components in the containment

) following an accident.

This chemical is an accident mitigator, not an accident initiator in that it is not used until after an accident has occurred. At the time it goes into solution, the j

_ accident has occurred, containment spray has been activated and water has  ;

j collected in the sump. Therefore, increasing the Technical Specification - t minimum amount verified to be in containment or changing the sample solution j , and sampie size will not involve a significant increase in the probability of an

accident previously evaluated.

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At the time TSP goes into solution, the accident has occurred, containment

[ spray has been activated and water has collected in the containment sump. At i

Waterford 3, the iodine partition factor is a constant 50% and does not vary with j pH as allowed in the Standard Review Plan (SRP) revision 1. The curve in SRP l l 6.5.2 revision 1 allows a partition factor of at least 50% for containment water at i a pH of 6.5 or less. The partition factor increases as pH rises. But, the curve is i based on sodium hydroxide which is much more reactive than TSP. Therefore,

, increasing the Technical Specification minimum amount verified to be in the j containment, and corresponding sample size, will not involve any increase in the i consequences of an accident because no credit is taken for reducing the amount j of volatized iodine normally associated with a 7.0 pH solution.

[ Therefore, the proposed change will not involve a significant increase j in the probability or consequences of any accident previously evaluated. j i

2. Will operation of the facility in accordance with this proposed change j create the possibility of a new or different type of accident from any accident

previously evaluated?

Response: No.

l The addition of more TSP does not represent a significant change in the configuration or operation of the plant. Trisodium phosphate dodecahydrate is currently present in the containment lower level. Design Change 3491 which  !

increases the storage capacity of the TSP storage baskets was evaluated in accordance with 10CFR50.59 and found not to involve an unreviewed safety question.

Boric acid acts as a buffer to prevent the pH from rising above approximately 8.1 as TSP is dissolved. An internal study (EC-S96-013 revision 0) has shown that I

given the " ratio of grams of TSP to liters of 3000 ppm boron solution" stays less than 5.6, TSP cannot increase pH above 8.2. As pH increases, components 4

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' composed of aluminum, zinc, or copper become vulnerable to corrosion. Branch Technical Position MTEB 6-1 implies that a solution pH greater than 7.5 enhances the chance for hydrogen generation as a result of aluminum corrosion.

Waterford 3 administratively limits the amount of aluminum in containment to minimize the amount of hydrogen expected during a DBA. Zinc is a component

~of the paint applied to surfaces inside containment. The hydrogen recombiner design basis includes 464 square feet (1040 pounds) of aluminum and 419,300 square feet (17,252 pounds) of metallic zinc. Estimates of the amount of hydrogen produced by the aluminum assumes that the corrosive agent is sodium hydroxide - a much more active chemical than is TSP. Thus, the amount of hydrogen expected in the FSAR for the hydrogen recombiner bounds what would actually be produced by TSP even at a pH of approximately 8.1.

The 4.5.2.d.3 proposed TSP to boron ratio assures that pH cannot rise above 8.1 as long as post accident in-containment boric acid solution concentration is no greater than 3011 ppm boron and no less than 1504 ppm boron. The main variable in post accident concentration (the difference between 1504 and 3011) is the concentration in the RCS at the time of the accident.

Therefore, the proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety?

Response: No Trisodium phosphate dodecahydrate is stored in the containment lower level to raise the pH of the sump and spray water following a LOCA. As the pH of the water increases, more radioactive iodine is kept in solution and the amount of airborne radioactive leakage is decreased. A neutral pH also reduces the hydrogen generation from the corrosion of the galvanized materials in containment. An additional advantage of a higher pH is the beneficial reduction in chloride stress corrosion cracking of metal components in the containment j following an accident. l Technical Specification 4.5.2.d.3 requires verification that a minimum volume of ;

TSP is contained in the storage baskets in containment. Nine previous runs of l surveillance requirement 4.5.2.d.4 (and similar tests) showed that the TSP i actually used in the plant properly neutralized a sample of water borated within j RWSP boron concentration limits. Boron concentrations of eight of the sample i

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' solutions used in these tests ranged from 1753 ppm to 2217 ppm and resulted in a pH of 7.02 or greater (The boron concentration of one test performed in 1986 l was unavailable.) The ratio 4 grams to 4 liters is the amount of TSP needed to j j bring the solution to a pH of at least 7 0 given that the solution is in the 1753 to '

l 2217 ppm Boron range. l l ,

i The amount of TSP in containment currently is adequate assuming that RCS i

- boric acid concentration stays below 454 ppm. However, the fuel cycle is nearly l over and a restart with a refreshed core would require substantially more boric ,

acid. We expect that the containment water would reach approximately 2400

! ppm under ideal circumstances during cycle 9. During cycle 10, boron J

! concentration in containment could reach 3011 under those same ideal conditions. As the maximum boron concentration increases, there is a non-

linear increase in the amount of TSP needed to raise solution pH to 7.0. Thus, )

we request that the minimum amount of TSP in containment required by  !

!- 4.5.2.d.3 to be increased from 97.5 cubic feet to 380 cubic feet. This change i

also proposes to adjust the 4.5.2.d.4 specified sample solution and the TSP - ,

' sample mass accordingly. This change will ensure the safety injection sump,-

when filled with water, will have an acceptable pH following a LOCA. The test ,

[ will not only demonstrate that TSP is in the baskets but also shows that the )

amount of TSP in containment can neutralize the solution expected in containment during any DBA.

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Therefore, the proposed change will not involve a reduction in a margin of

safety. The amount of iodine kept in solution during a DBA is limited to 50%.

[ Note, the pH scale is logarithmic so that the amount of TSP needed to raise pH to 7.0 is more than three times the amount needed to reach 6.5. Furthermore, l

j the amount of hydrogen generated during a DBA is over estimated by the j analysis when it used sodium hydroxide as the corrosive agent rather than TSP.

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Safety and Sionificant Hazards Determination Based on the above safety analysis, it is concluded that: (1) the proposed change does not constitute a significant hazards consideration as defined by 10CFR50.92; and (2) there is a reasonable assurance that the health and safety of the public will not be endangered by the proposed change; and (3) this action will not result in a condition which significantly alters the impact of the station on the environment as described in  !

the NRC final environmental statement. ,

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