ML20058E988
| ML20058E988 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 11/02/1990 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML20058F000 | List: |
| References | |
| NUDOCS 9011080049 | |
| Download: ML20058E988 (2) | |
Text
{{#Wiki_filter:[ L s s w m $[ M -{ 1 %[. DRESDEN II DPR-19 l Amendment No.113 - 1 h r ["< 3.4. LIMITING CONDITION FOR OPERATION BASES 'l s - A., vT.he design' objective.of the standby = liquid control system is to 'l provide the capability of bringing the reactor from full-power to a cold'. xenon-free shutdown assuming that none of the withdrawn control rods can be inserted. To meet this objective, the liquid control-system is designed to inject a quantity of boron which produces a i' concentration'of no less than 600 ppm of boron.in the reactor core in 3 Lless than 100 minutes. 600 ppm boron concentration in the reactor-1 F core'isLrequired to bring the reactor from full power to a 3%' delta k d
- or.more subcritical condition considerii,g the hot to cold reactivity-swing and xenon poisoning.- An additional margin of 25% boron is 9
vadded to compensate'for possible' imperfect mixing of the chemical M solution tin-the' reactor water, making the total concentration 750 ppm n ', of boron in the reactor core. A minimum quantity of 3329 gallons _of ) , solution having a 14 wt. percent sodium pentaborate concentration.is j ' required to meet this shutdown'_ requirement.. i fi:0 <For a! req' uired pumping rate of 40 gpm per pump, 3329 gallons of at i lleast 14 wt. percent solution will' be inserted in less than 100 min-L "utes.: sThis insertion rate of boron solu' tion will override the rate j i',
- of reactivity insertion'due'to cool down of.the' reactor following the 1
E-xenon peak. Two pump operation will enable faster reactor shutdown-1 p for;ATWS events. The minimum' volume required in'the storage tank i a shall be 3605' gallons-(276'are contained below the pump-suction and, 1 W ' Ltherefore, Lcannot"bel inserted); The monthly; pump minimum flowrate 4 M test shall require'a. minimum flowrate of:40 gpm per pump. This r> - requirement,; combinediwith_ the solution ; concentration requirement of ~ J ~ at:1 east 14 wtn percent, will demonstrate that the'StandbytLiquid s Control System meets the requirementsLof 10 CFR 50.62. 4 ~ g(r B'oron concentration, solution _ temperature,i and; volume -Jc4 checked on l f* M a frequency to assure'a:highireliability of operation of tne system-j tshouldtit ever be: required. Experience with pump operability indi-4 cates t_ hat monthly' testing is' adequate _ to: detect _if. failures' have
- y y'
s M s occurred. 1, 1 y Y. Components ofLthe system are checked periodically as, described M 'above and:make'atfunctional test of-the entire system on a frequency l 4 W ofiless than once during.each operating cycle' unnecessary. -A test of ?one installed explosive charge is made at least once during each operating cycle to assure that the charges have not deteriorated,'the actuation circuit is functioning properly, theLvalve; functions q s cproperly, land'no' flow blockages. exist. The replacement charge will-H
- x.
'be: selected from:a' batch for which there has been a successful test firing. Recommendations of the vendor shall be followed in main-taining a five year' life of 'the explosive charges.. A continual check ?. of the firing' circuit continuity is provided by pilot lights in the control room, o { I c' i B 3/4.4-6 l Ohg,9 olio 2CK0500gg'j7 ^ l p. P 4
jy DRESDEN III DPR-25 Amendment No. 109 3.4 LIMITING CONDITION FOR OPERATION BASES A. 'ine design objective of the standby liquid control system is to pro-vide the capability of bringing the reactor from full power to a cold, xenon-free shutdown assuming that none of the withdrawn conteol rods can be inserted. To meet this objective, the liquid control system is designed to inject a quantity of boron which produces a concentra-tion of no.less than 600 ppm of boron in the reactor core in less .than 100 minutes. 600 ppm boron concentration in the reactor core is required to bring the reactor from full power to a 3% delta k or more suberitical condition considering the hot.to cold reactivity swing and xenon poisoning. An additional margin of 25% boron is added to compensate for possible imperfect mixing of the chemical solution in the reactor water, making the total concentration 750 ppm of boron in the reactor core. A minimum quantity of 3329 gallons of solution 4 having a 14 wt. percent sodium pentaborate etncentration is required 4 .to meet this shutdown requirement. For a required pumping rate of.40 gpm per pump, 3329 gallons of at least 14 wt. percent solution will be inserted in less than 100 minutes. This insertion rate of boron solution will override the rate of reactivity insertion due to cool down of the reactor following i i the >.aon peak.. Two pump operation will enable faster reactor shutdown for ATWS events. The minimum volume required in the storage tank.shall be' 3605 gallons (276 are contained below the pump suction and, therefore, cannot be inserted). The monthly pump minimum flow-rate test-shall require a minimum flowrate of 40 gpm per pump..This requirement, combined with the~ solution concentration requirement of at least 14 wt. percent, will-demonstrate that:the Standby Liquid
- w Control System meets the requirements of 10 CFR 50.62.
. Boron concentration, solution temperature, and volume are checked on a frequency to assure a high reliability of operation of tha system b should it ever be required. Experience with pump operability indi-l cates that monthly testing is adequate to detect if failures have j y occurred. E Components 1of the system are checked periodically as described above i and make a functional test of the entire system on a' frequency of less than once during each operating cycle unnecessary. A test of one installed explosive charge is made at least once during each operating-cycle to. assure that the charges have not. deteriorated, the actuation O circuit is functioning properly, the valve functions properly, and no flow blockages exist. The replacement charge sill be selected from e
- batch for which there has been a successful test firing.
Recommenda - 1 tions of the vendor shall be followed in maintaining a five year life of the explosive charges. A continual check of the firing circuit l continuity-is provided by pilot lights in the control room. 1 B 3/4.4-6 ___,,.,_m_ _}}